1. What is .NET Framework?
The .NET Framework has two main components: the common language runtime and the .NET Framework class library.
You can think of the runtime as an agent that manages code at execution time, providing core services such as memory management, thread management, and remoting, while also enforcing strict type safety and other forms of code accuracy that ensure security and robustness.
The class library, is a comprehensive, object-oriented collection of reusable types that you can use to develop applications ranging from traditional command-line or graphical user interface (GUI) applications to applications based on the latest innovations provided by ASP.NET, such as Web Forms and XML Web services.
2. What is CLR, CTS, CLS?
The .NET Framework provides a runtime environment called the Common Language Runtime or CLR (similar to the Java Virtual Machine or JVM in Java), which handles the execution of code and provides useful services for the implementation of the program. CLR takes care of code management at program execution and provides various beneficial services such as memory management, thread management, security management, code verification, compilation, and other system services. The managed code that targets CLR benefits from useful features such as cross-language integration, cross-language exception handling, versioning, enhanced security, deployment support, and debugging.
Common Type System (CTS) describes how types are declared, used and managed in the runtime and facilitates cross-language integration, type safety, and high performance code execution.
The CLS is simply a specification that defines the rules to support language integration in such a way that programs written in any language, yet can interoperate with one another, taking full advantage of inheritance, polymorphism, exceptions, and other features. These rules and the specification are documented in the ECMA proposed standard document, "Partition I Architecture", http://msdn.microsoft.com/net/ecma/
3. What are the new features of Framework 1.1 ?
1. Native Support for Developing Mobile Web Applications
2. Enable Execution of Windows Forms Assemblies Originating from the Internet
Assemblies originating from the Internet zone—for example, Microsoft Windows® Forms controls embedded in an Internet-based Web page or Windows Forms assemblies hosted on an Internet Web server and loaded either through the Web browser or programmatically using the System.Reflection.Assembly.LoadFrom() method—now receive sufficient permission to execute in a semi-trusted manner. Default security policy has been changed so that assemblies assigned by the common language runtime (CLR) to the Internet zone code group now receive the constrained permissions associated with the Internet permission set. In the .NET Framework 1.0 Service Pack 1 and Service Pack 2, such applications received the permissions associated with the Nothing permission set and could not execute.
3. Enable Code Access Security for ASP.NET Applications
Systems administrators can now use code access security to further lock down the permissions granted to ASP.NET Web applications and Web services. Although the operating system account under which an application runs imposes security restrictions on the application, the code access security system of the CLR can enforce additional restrictions on selected application resources based on policies specified by systems administrators. You can use this feature in a shared server environment (such as an Internet service provider (ISP) hosting multiple Web applications on one server) to isolate separate applications from one another, as well as with stand-alone servers where you want applications to run with the minimum necessary privileges.
4. Native Support for Communicating with ODBC and Oracle Databases
5. Unified Programming Model for Smart Client Application Development
The Microsoft .NET Compact Framework brings the CLR, Windows Forms controls, and other .NET Framework features to small devices. The .NET Compact Framework supports a large subset of the .NET Framework class library optimized for small devices.
6. Support for IPv6
The .NET Framework 1.1 supports the emerging update to the Internet Protocol, commonly referred to as IP version 6, or simply IPv6. This protocol is designed to significantly increase the address space used to identify communication endpoints in the Internet to accommodate its ongoing growth.
http://msdn.microsoft.com/netframework/technologyinfo/Overview/whatsnew.aspx
4. Is .NET a runtime service or a development platform?
Ans: It's both and actually a lot more. Microsoft .NET includes a new way of delivering software and services to businesses and consumers. A part of Microsoft.NET is the .NET Frameworks. The .NET frameworks SDK consists of two parts: the .NET common language runtime and the .NET class library. In addition, the SDK also includes command-line compilers for C#, C++, JScript, and VB. You use these compilers to build applications and components. These components require the runtime to execute so this is a development platform.
5. What is MSIL, IL?
When compiling to managed code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is a CPU-independent set of instructions that can be efficiently converted to native code. MSIL includes instructions for loading, storing, initializing, and calling methods on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operations. Microsoft intermediate language (MSIL) is a language used as the output of a number of compilers and as the input to a just-in-time (JIT) compiler. The common language runtime includes a JIT compiler for converting MSIL to native code.
6. Can I write IL programs directly?
Yes. Peter Drayton posted this simple example to the DOTNET mailing list:
.assembly MyAssembly {}
.class MyApp {
.method static void Main() {
.entrypoint
ldstr "Hello, IL!"
call void System.Console::WriteLine(class System.Object)
ret
}
}
Just put this into a file called hello.il, and then run ilasm hello.il. An exe assembly will be generated.
Can I do things in IL that I can't do in C#?
Yes. A couple of simple examples are that you can throw exceptions that are not derived from System.Exception, and you can have non-zero-based arrays.
7. What is JIT (just in time)? how it works?
Before Microsoft intermediate language (MSIL) can be executed, it must be converted by a .NET Framework just-in-time (JIT) compiler to native code, which is CPU-specific code that runs on the same computer architecture as the JIT compiler.
Rather than using time and memory to convert all the MSIL in a portable executable (PE) file to native code, it converts the MSIL as it is needed during execution and stores the resulting native code so that it is accessible for subsequent calls.
The runtime supplies another mode of compilation called install-time code generation. The install-time code generation mode converts MSIL to native code just as the regular JIT compiler does, but it converts larger units of code at a time, storing the resulting native code for use when the assembly is subsequently loaded and executed.
As part of compiling MSIL to native code, code must pass a verification process unless an administrator has established a security policy that allows code to bypass verification. Verification examines MSIL and metadata to find out whether the code can be determined to be type safe, which means that it is known to access only the memory locations it is authorized to access.
8. What is strong name?
A name that consists of an assembly's identity—its simple text name, version number, and culture information (if provided)—strengthened by a public key and a digital signature generated over the assembly.
9. What is portable executable (PE)?
The file format defining the structure that all executable files (EXE) and Dynamic Link Libraries (DLL) must use to allow them to be loaded and executed by Windows. PE is derived from the Microsoft Common Object File Format (COFF). The EXE and DLL files created using the .NET Framework obey the PE/COFF formats and also add additional header and data sections to the files that are only used by the CLR. The specification for the PE/COFF file formats is available at http://www.microsoft.com/whdc/hwdev/hardware/pecoffdown.mspx
10. What is Event - Delegate? clear syntax for writing a event delegate
The event keyword lets you specify a delegate that will be called upon the occurrence of some "event" in your code. The delegate can have one or more associated methods that will be called when your code indicates that the event has occurred. An event in one program can be made available to other programs that target the .NET Framework Common Language Runtime.
// keyword_delegate.cs
// delegate declaration
delegate void MyDelegate(int i);
11. class Program
12. {
13. public static void Main()
14. {
15. TakesADelegate(new MyDelegate(DelegateFunction));
16. }
17. public static void TakesADelegate(MyDelegate SomeFunction)
18. {
19. SomeFunction(21);
20. }
21. public static void DelegateFunction(int i)
22. {
23. System.Console.WriteLine("Called by delegate with number: {0}.", i);
24. }
}
25. What is Code Access Security (CAS)?
CAS is the part of the .NET security model that determines whether or not a piece of code is allowed to run, and what resources it can use when it is running. For example, it is CAS that will prevent a .NET web applet from formatting your hard disk.
How does CAS work?
The CAS security policy revolves around two key concepts - code groups and permissions. Each .NET assembly is a member of a particular code group, and each code group is granted the permissions specified in a named permission set.
For example, using the default security policy, a control downloaded from a web site belongs to the 'Zone - Internet' code group, which adheres to the permissions defined by the 'Internet' named permission set. (Naturally the 'Internet' named permission set represents a very restrictive range of permissions.)
Who defines the CAS code groups?
Microsoft defines some default ones, but you can modify these and even create your own. To see the code groups defined on your system, run 'caspol -lg' from the command-line. On my syystem it looks like this:
26. Level = Machine
27. Code Groups:
28.
29. 1. All code: Nothing
30. 1.1. Zone - MyComputer: FullTrust
31. 1.1.1. Honor SkipVerification requests: SkipVerification
32. 1.2. Zone - Intranet: LocalIntranet
33. 1.3. Zone - Internet: Internet
34. 1.4. Zone - Untrusted: Nothing
35. 1.5. Zone - Trusted: Internet
36. 1.6. StrongName - 0024000004800000940000000602000000240000525341310004000003
37. 000000CFCB3291AA715FE99D40D49040336F9056D7886FED46775BC7BB5430BA4444FEF8348EBD06
38. F962F39776AE4DC3B7B04A7FE6F49F25F740423EBF2C0B89698D8D08AC48D69CED0FC8F83B465E08
39. 07AC11EC1DCC7D054E807A43336DDE408A5393A48556123272CEEEE72F1660B71927D38561AABF5C
AC1DF1734633C602F8F2D5: Everything
Note the hierarchy of code groups - the top of the hierarchy is the most general ('All code'), which is then sub-divided into several groups, each of which in turn can be sub-divided. Also note that (somewhat counter-intuitively) a sub-group can be associated with a more permissive permission set than its parent.
How do I define my own code group?
Use caspol. For example, suppose you trust code from www.mydomain.com and you want it have full access to your system, but you want to keep the default restrictions for all other internet sites. To achieve this, you would add a new code group as a sub-group of the 'Zone - Internet' group, like this:
caspol -ag 1.3 -site www.mydomain.com FullTrust
Now if you run caspol -lg you will see that the new group has been added as group 1.3.1:
...
1.3. Zone - Internet: Internet
1.3.1. Site - www.mydomain.com: FullTrust
...
Note that the numeric label (1.3.1) is just a caspol invention to make the code groups easy to manipulate from the command-line. The underlying runtime never sees it.
How do I change the permission set for a code group?
Use caspol. If you are the machine administrator, you can operate at the 'machine' level - which means not only that the changes you make become the default for the machine, but also that users cannot change the permissions to be more permissive. If you are a normal (non-admin) user you can still modify the permissions, but only to make them more restrictive. For example, to allow intranet code to do what it likes you might do this:
caspol -cg 1.2 FullTrust
Note that because this is more permissive than the default policy (on a standard system), you should only do this at the machine level - doing it at the user level will have no effect.
Can I create my own permission set?
Yes. Use caspol -ap, specifying an XML file containing the permissions in the permission set. To save you some time, here is a sample file corresponding to the 'Everything' permission set - just edit to suit your needs. When you have edited the sample, add it to the range of available permission sets like this:
caspol -ap samplepermset.xml
Then, to apply the permission set to a code group, do something like this:
caspol -cg 1.3 SamplePermSet (By default, 1.3 is the 'Internet' code group)
I'm having some trouble with CAS. How can I diagnose my problem?
Caspol has a couple of options that might help. First, you can ask caspol to tell you what code group an assembly belongs to, using caspol -rsg. Similarly, you can ask what permissions are being applied to a particular assembly using caspol -rsp.
I can't be bothered with all this CAS stuff. Can I turn it off?
Yes, as long as you are an administrator. Just run:
caspol -s off
http://www.codeproject.com/dotnet/UB_CAS_NET.asp
40. Which namespace is the base class for .net Class library?
Ans: system.object
41. What are object pooling and connection pooling and difference? Where do we set the Min and Max Pool size for connection pooling?
Object pooling is a COM+ service that enables you to reduce the overhead of creating each object from scratch. When an object is activated, it is pulled from the pool. When the object is deactivated, it is placed back into the pool to await the next request. You can configure object pooling by applying the ObjectPoolingAttribute attribute to a class that derives from the System.EnterpriseServices.ServicedComponent class.
Object pooling lets you control the number of connections you use, as opposed to connection pooling, where you control the maximum number reached.
Following are important differences between object pooling and connection pooling:
? Creation. When using connection pooling, creation is on the same thread, so if there is nothing in the pool, a connection is created on your behalf. With object pooling, the pool might decide to create a new object. However, if you have already reached your maximum, it instead gives you the next available object. This is crucial behavior when it takes a long time to create an object, but you do not use it for very long.
? Enforcement of minimums and maximums. This is not done in connection pooling. The maximum value in object pooling is very important when trying to scale your application. You might need to multiplex thousands of requests to just a few objects. (TPC/C benchmarks rely on this.)
COM+ object pooling is identical to what is used in .NET Framework managed SQL Client connection pooling. For example, creation is on a different thread and minimums and maximums are enforced.
42. What is Application Domain?
The primary purpose of the AppDomain is to isolate an application from other applications. Win32 processes provide isolation by having distinct memory address spaces. This is effective, but it is expensive and doesn't scale well. The .NET runtime enforces AppDomain isolation by keeping control over the use of memory - all memory in the AppDomain is managed by the .NET runtime, so the runtime can ensure that AppDomains do not access each other's memory.
Objects in different application domains communicate either by transporting copies of objects across application domain boundaries, or by using a proxy to exchange messages.
MarshalByRefObject is the base class for objects that communicate across application domain boundaries by exchanging messages using a proxy. Objects that do not inherit from MarshalByRefObject are implicitly marshal by value. When a remote application references a marshal by value object, a copy of the object is passed across application domain boundaries.
How does an AppDomain get created?
AppDomains are usually created by hosts. Examples of hosts are the Windows Shell, ASP.NET and IE. When you run a .NET application from the command-line, the host is the Shell. The Shell creates a new AppDomain for every application.
AppDomains can also be explicitly created by .NET applications. Here is a C# sample which creates an AppDomain, creates an instance of an object inside it, and then executes one of the object's methods. Note that you must name the executable 'appdomaintest.exe' for this code to work as-is.
43. using System;
44. using System.Runtime.Remoting;
45.
46. public class CAppDomainInfo : MarshalByRefObject
47. {
48. public string GetAppDomainInfo()
49. {
50. return "AppDomain = " + AppDomain.CurrentDomain.FriendlyName;
51. }
52. }
53. public class App
54. {
55. public static int Main()
56. {
57. AppDomain ad = AppDomain.CreateDomain( "Andy's new domain", null, null );
58. ObjectHandle oh = ad.CreateInstance( "appdomaintest", "CAppDomainInfo" );
59. CAppDomainInfo adInfo = (CAppDomainInfo)(oh.Unwrap());
60. string info = adInfo.GetAppDomainInfo();
61. Console.WriteLine( "AppDomain info: " + info );
62. return 0;
63. }
}
64. What is serialization in .NET? What are the ways to control serialization?
Serialization is the process of converting an object into a stream of bytes. Deserialization is the opposite process of creating an object from a stream of bytes. Serialization/Deserialization is mostly used to transport objects (e.g. during remoting), or to persist objects (e.g. to a file or database).Serialization can be defined as the process of storing the state of an object to a storage medium. During this process, the public and private fields of the object and the name of the class, including the assembly containing the class, are converted to a stream of bytes, which is then written to a data stream. When the object is subsequently deserialized, an exact clone of the original object is created.
? Binary serialization preserves type fidelity, which is useful for preserving the state of an object between different invocations of an application. For example, you can share an object between different applications by serializing it to the clipboard. You can serialize an object to a stream, disk, memory, over the network, and so forth. Remoting uses serialization to pass objects "by value" from one computer or application domain to another.
? XML serialization serializes only public properties and fields and does not preserve type fidelity. This is useful when you want to provide or consume data without restricting the application that uses the data. Because XML is an open standard, it is an attractive choice for sharing data across the Web. SOAP is an open standard, which makes it an attractive choice.
There are two separate mechanisms provided by the .NET class library - XmlSerializer and SoapFormatter/BinaryFormatter. Microsoft uses XmlSerializer for Web Services, and uses SoapFormatter/BinaryFormatter for remoting. Both are available for use in your own code.
Why do I get errors when I try to serialize a Hashtable?
XmlSerializer will refuse to serialize instances of any class that implements IDictionary, e.g. Hashtable. SoapFormatter and BinaryFormatter do not have this restriction.
65. What is exception handling?
When an exception occurs, the system searches for the nearest catch clause that can handle the exception, as determined by the run-time type of the exception. First, the current method is searched for a lexically enclosing try statement, and the associated catch clauses of the try statement are considered in order. If that fails, the method that called the current method is searched for a lexically enclosing try statement that encloses the point of the call to the current method. This search continues until a catch clause is found that can handle the current exception, by naming an exception class that is of the same class, or a base class, of the run-time type of the exception being thrown. A catch clause that doesn't name an exception class can handle any exception.
Once a matching catch clause is found, the system prepares to transfer control to the first statement of the catch clause. Before execution of the catch clause begins, the system first executes, in order, any finally clauses that were associated with try statements more nested that than the one that caught the exception.
Exceptions that occur during destructor execution are worth special mention. If an exception occurs during destructor execution, and that exception is not caught, then the execution of that destructor is terminated and the destructor of the base class (if any) is called. If there is no base class (as in the case of the object type) or if there is no base class destructor, then the exception is discarded.
66. What is Assembly?
Assemblies are the building blocks of .NET Framework applications; they form the fundamental unit of deployment, version control, reuse, activation scoping, and security permissions. An assembly is a collection of types and resources that are built to work together and form a logical unit of functionality. An assembly provides the common language runtime with the information it needs to be aware of type implementations. To the runtime, a type does not exist outside the context of an assembly.
Assemblies are a fundamental part of programming with the .NET Framework. An assembly performs the following functions:
? It contains code that the common language runtime executes. Microsoft intermediate language (MSIL) code in a portable executable (PE) file will not be executed if it does not have an associated assembly manifest. Note that each assembly can have only one entry point (that is, DllMain, WinMain, or Main).
? It forms a security boundary. An assembly is the unit at which permissions are requested and granted.
? It forms a type boundary. Every type's identity includes the name of the assembly in which it resides. A type called MyType loaded in the scope of one assembly is not the same as a type called MyType loaded in the scope of another assembly.
? It forms a reference scope boundary. The assembly's manifest contains assembly metadata that is used for resolving types and satisfying resource requests. It specifies the types and resources that are exposed outside the assembly. The manifest also enumerates other assemblies on which it depends.
? It forms a version boundary. The assembly is the smallest versionable unit in the common language runtime; all types and resources in the same assembly are versioned as a unit. The assembly's manifest describes the version dependencies you specify for any dependent assemblies.
? It forms a deployment unit. When an application starts, only the assemblies that the application initially calls must be present. Other assemblies, such as localization resources or assemblies containing utility classes, can be retrieved on demand. This allows applications to be kept simple and thin when first downloaded.
? It is the unit at which side-by-side execution is supported.
Assemblies can be static or dynamic. Static assemblies can include .NET Framework types (interfaces and classes), as well as resources for the assembly (bitmaps, JPEG files, resource files, and so on). Static assemblies are stored on disk in PE files. You can also use the .NET Framework to create dynamic assemblies, which are run directly from memory and are not saved to disk before execution. You can save dynamic assemblies to disk after they have executed.
There are several ways to create assemblies. You can use development tools, such as Visual Studio .NET, that you have used in the past to create .dll or .exe files. You can use tools provided in the .NET Framework SDK to create assemblies with modules created in other development environments. You can also use common language runtime APIs, such as Reflection.Emit, to create dynamic assemblies.
67. What are the contents of assembly?
In general, a static assembly can consist of four elements:
? The assembly manifest, which contains assembly metadata.
? Type metadata.
? Microsoft intermediate language (MSIL) code that implements the types.
? A set of resources.
68. What are the different types of assemblies?
Private, Public/Shared, Satellite
69. What is the difference between a private assembly and a shared assembly?
0. Location and visibility: A private assembly is normally used by a single application, and is stored in the application's directory, or a sub-directory beneath. A shared assembly is normally stored in the global assembly cache, which is a repository of assemblies maintained by the .NET runtime. Shared assemblies are usually libraries of code which many applications will find useful, e.g. the .NET framework classes.
1. Versioning: The runtime enforces versioning constraints only on shared assemblies, not on private assemblies.
70. What are Satellite Assemblies? How you will create this? How will you get the different language strings?
Satellite assemblies are often used to deploy language-specific resources for an application. These language-specific assemblies work in side-by-side execution because the application has a separate product ID for each language and installs satellite assemblies in a language-specific subdirectory for each language. When uninstalling, the application removes only the satellite assemblies associated with a given language and .NET Framework version. No core .NET Framework files are removed unless the last language for that .NET Framework version is being removed.
(For example, English and Japanese editions of the .NET Framework version 1.1 share the same core files. The Japanese .NET Framework version 1.1 adds satellite assemblies with localized resources in a \ja subdirectory. An application that supports the .NET Framework version 1.1, regardless of its language, always uses the same core runtime files.)
http://www.ondotnet.com/lpt/a/2637
**
71. How will u load dynamic assembly? How will create assemblies at run time?
**
72. What is Assembly manifest? what all details the assembly manifest will contain?
Every assembly, whether static or dynamic, contains a collection of data that describes how the elements in the assembly relate to each other. The assembly manifest contains this assembly metadata. An assembly manifest contains all the metadata needed to specify the assembly's version requirements and security identity, and all metadata needed to define the scope of the assembly and resolve references to resources and classes. The assembly manifest can be stored in either a PE file (an .exe or .dll) with Microsoft intermediate language (MSIL) code or in a standalone PE file that contains only assembly manifest information.
It contains Assembly name, Version number, Culture, Strong name information, List of all files in the assembly, Type reference information, Information on referenced assemblies.
73. Difference between assembly manifest & metadata?
assembly manifest - An integral part of every assembly that renders the assembly self-describing. The assembly manifest contains the assembly's metadata. The manifest establishes the assembly identity, specifies the files that make up the assembly implementation, specifies the types and resources that make up the assembly, itemizes the compile-time dependencies on other assemblies, and specifies the set of permissions required for the assembly to run properly. This information is used at run time to resolve references, enforce version binding policy, and validate the integrity of loaded assemblies. The self-describing nature of assemblies also helps makes zero-impact install and XCOPY deployment feasible.
metadata - Information that describes every element managed by the common language runtime: an assembly, loadable file, type, method, and so on. This can include information required for debugging and garbage collection, as well as security attributes, marshaling data, extended class and member definitions, version binding, and other information required by the runtime.
74. What is Global Assembly Cache (GAC) and what is the purpose of it? (How to make an assembly to public? Steps) How more than one version of an assembly can keep in same place?
Each computer where the common language runtime is installed has a machine-wide code cache called the global assembly cache. The global assembly cache stores assemblies specifically designated to be shared by several applications on the computer. You should share assemblies by installing them into the global assembly cache only when you need to.
Steps
- Create a strong name using sn.exe tool
eg: sn -k keyPair.snk
- with in AssemblyInfo.cs add the generated file name
eg: [assembly: AssemblyKeyFile("abc.snk")]
- recompile project, then install it to GAC by either
drag & drop it to assembly folder (C:\WINDOWS\assembly OR C:\WINNT\assembly) (shfusion.dll tool)
or
gacutil -i abc.dll
75. If I have more than one version of one assemblies, then how'll I use old version (how/where to specify version number?)in my application?
**
76. How to find methods of a assembly file (not using ILDASM)
Reflection
77. What is Garbage Collection in .Net? Garbage collection process?
The process of transitively tracing through all pointers to actively used objects in order to locate all objects that can be referenced, and then arranging to reuse any heap memory that was not found during this trace. The common language runtime garbage collector also compacts the memory that is in use to reduce the working space needed for the heap.
78. What is Reflection in .NET? Namespace? How will you load an assembly which is not referenced by current assembly?
All .NET compilers produce metadata about the types defined in the modules they produce. This metadata is packaged along with the module (modules in turn are packaged together in assemblies), and can be accessed by a mechanism called reflection. The System.Reflection namespace contains classes that can be used to interrogate the types for a module/assembly.
Using reflection to access .NET metadata is very similar to using ITypeLib/ITypeInfo to access type library data in COM, and it is used for similar purposes - e.g. determining data type sizes for marshaling data across context/process/machine boundaries.
Reflection can also be used to dynamically invoke methods (see System.Type.InvokeMember), or even create types dynamically at run-time (see System.Reflection.Emit.TypeBuilder).
79. What is Custom attribute? How to create? If I'm having custom attribute in an assembly, how to say that name in the code?
A: The primary steps to properly design custom attribute classes are as follows:
. Applying the AttributeUsageAttribute ([AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true)])
a. Declaring the attribute. (class public class MyAttribute : System.Attribute { // . . . })
b. Declaring constructors (public MyAttribute(bool myvalue) { this.myvalue = myvalue; })
c. Declaring properties
public bool MyProperty
{
get {return this.myvalue;}
set {this.myvalue = value;}
}
The following example demonstrates the basic way of using reflection to get access to custom attributes.
class MainClass
{
public static void Main()
{
System.Reflection.MemberInfo info = typeof(MyClass);
object[] attributes = info.GetCustomAttributes();
for (int i = 0; i < b="1;" b="5;" b="i;" l1 =" (uint)" variable="new" variable="new" count =" 1;" count =" 1;" fs =" New" xlapp =" CreateObject(" url="/library/en-us/cpguide/html/cpconfinalizemethodscdestructors.asp" nwindconn =" new" source="localhost;" security="SSPI;" catalog="northwind" parentcol =" DataSet1.Tables[" childcol =" DataSet1.Tables[" relcustorder =" new" myreader =" myCommand.ExecuteReader();" cookieless="true">
http://samples.gotdotnet.com/quickstart/aspplus/doc/stateoverview.aspx
10. How you will handle session when deploying application in more than a server? Describe session handling in a webfarm, how does it work and what are the limits?
By default, ASP.NET will store the session state in the same process that processes the request, just as ASP does. Additionally, ASP.NET can store session data in an external process, which can even reside on another machine. To enable this feature:
? Start the ASP.NET state service, either using the Services snap-in or by executing "net start aspnet_state" on the command line. The state service will by default listen on port 42424. To change the port, modify the registry key for the service: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\aspnet_state\Parameters\Port
? Set the mode attribute of the
? Configure the stateConnectionString attribute with the values of the machine on which you started aspnet_state.
The following sample assumes that the state service is running on the same machine as the Web server ("localhost") and uses the default port (42424):
Note that if you try the sample above with this setting, you can reset the Web server (enter iisreset on the command line) and the session state value will persist.
**
11. What method do you use to explicitly kill a users session?
Abandon()
12. What are the different ways you would consider sending data across pages in ASP (i.e between 1.asp to 2.asp)?
Session
public properties
13. What is State Management in .Net and how many ways are there to maintain a state in .Net? What is view state?
Web pages are recreated each time the page is posted to the server. In traditional Web programming, this would ordinarily mean that all information associated with the page and the controls on the page would be lost with each round trip.
To overcome this inherent limitation of traditional Web programming, the ASP.NET page framework includes various options to help you preserve changes — that is, for managing state. The page framework includes a facility called view state that automatically preserves property values of the page and all the controls on it between round trips.
However, you will probably also have application-specific values that you want to preserve. To do so, you can use one of the state management options.
Client-Based State Management Options:
View State
Hidden Form Fields
Cookies
Query Strings
Server-Based State Management Options
Application State
Session State
Database Support
14. What are the disadvantages of view state / what are the benefits?
Automatic view-state management is a feature of server controls that enables them to repopulate their property values on a round trip (without you having to write any code). This feature does impact performance, however, since a server control's view state is passed to and from the server in a hidden form field. You should be aware of when view state helps you and when it hinders your page's performance.
15. When maintaining session through Sql server, what is the impact of Read and Write operation on Session objects? will performance degrade?
Maintaining state using database technology is a common practice when storing user-specific information where the information store is large. Database storage is particularly useful for maintaining long-term state or state that must be preserved even if the server must be restarted.
**
16. What are the contents of cookie?
**
17. How do you create a permanent cookie?
**
18. What is ViewState? What does the "EnableViewState" property do? Why would I want it on or off?
**
19. Explain the differences between Server-side and Client-side code?
Server side code will process at server side & it will send the result to client. Client side code (javascript) will execute only at client side.
20. Can you give an example of what might be best suited to place in the Application_Start and Session_Start subroutines?
**
21. Which ASP.NET configuration options are supported in the ASP.NET implementation on the shared web hosting platform?
A: Many of the ASP.NET configuration options are not configurable at the site, application or subdirectory level on the shared hosting platform. Certain options can affect the security, performance and stability of the server and, therefore cannot be changed. The following settings are the only ones that can be changed in your site’s web.config file (s):
browserCaps
clientTarget
pages
customErrors
globalization
authorization
authentication
webControls
webServices
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconaspnetconfiguration.asp
22. Briefly describe the role of global.asax?
23. How can u debug your .net application?
24. How do u deploy your asp.net application?
25. Where do we store our connection string in asp.net application?
26. Various steps taken to optimize a web based application (caching, stored procedure etc.)
27. How does ASP.NET framework maps client side events to Server side events.
(Security)
28. Security types in ASP/ASP.NET? Different Authentication modes?
29. How .Net has implemented security for web applications?
30. How to do Forms authentication in asp.net?
31. Explain authentication levels in .net ?
32. Explain autherization levels in .net ?
33. What is Role-Based security?
A role is a named set of principals that have the same privileges with respect to security (such as a teller or a manager). A principal can be a member of one or more roles. Therefore, applications can use role membership to determine whether a principal is authorized to perform a requested action.
**
34. How will you do windows authentication and what is the namespace? If a user is logged under integrated windows authentication mode, but he is still not able to logon, what might be the possible cause for this? In ASP.Net application how do you find the name of the logged in person under windows authentication?
35. What are the different authentication modes in the .NET environment?
36.
37.
41. requireSSL="true|false"
42. slidingExpiration="true|false">
43.
44.
45.
46.
47.
Attribute Option Description
mode Controls the default authentication mode for an application.
Windows Specifies Windows authentication as the default authentication mode. Use this mode when using any form of Microsoft Internet Information Services (IIS) authentication: Basic, Digest, Integrated Windows authentication (NTLM/Kerberos), or certificates.
Forms Specifies ASP.NET forms-based authentication as the default authentication mode.
Passport Specifies Microsoft Passport authentication as the default authentication mode.
None Specifies no authentication. Only anonymous users are expected or applications can handle events to provide their own authentication.
48. How do you specify whether your data should be passed as Query string and Forms (Mainly about POST and GET)
Through attribute tag of form tag.
49. What is the other method, other than GET and POST, in ASP.NET?
50. What are validator? Name the Validation controls in asp.net? How do u disable them? Will the asp.net validators run in server side or client side? How do you do Client-side validation in .Net? How to disable validator control by client side JavaScript?
A set of server controls included with ASP.NET that test user input in HTML and Web server controls for programmer-defined requirements. Validation controls perform input checking in server code. If the user is working with a browser that supports DHTML, the validation controls can also perform validation ("EnableClientScript" property set to true/false) using client script.
The following validation controls are available in asp.net:
RequiredFieldValidator Control, CompareValidator Control, RangeValidator Control, RegularExpressionValidator Control, CustomValidator Control, ValidationSummary Control.
51. Which two properties are there on every validation control?
ControlToValidate, ErrorMessage
52. How do you use css in asp.net?
Within the section of an HTML document that will use these styles, add a link to this external CSS style sheet that
follows this form:
MyStyles.css is the name of your external CSS style sheet.
53. How do you implement postback with a text box? What is postback and usestate?
Make AutoPostBack property to true
54. How can you debug an ASP page, without touching the code?
55. What is SQL injection?
An SQL injection attack "injects" or manipulates SQL code by adding unexpected SQL to a query.
Many web pages take parameters from web user, and make SQL query to the database. Take for instance when a user login, web page that user name and password and make SQL query to the database to check if a user has valid name and password.
Username: ' or 1=1 ---
Password: [Empty]
This would execute the following query against the users table:
select count(*) from users where userName='' or 1=1 --' and userPass=''
56. How can u handle Exceptions in Asp.Net?
57. How can u handle Un Managed Code Exceptions in ASP.Net?
58. Asp.net - How to find last error which occurred?
A: Server.GetLastError();
[C#]
Exception LastError;
String ErrMessage;
LastError = Server.GetLastError();
if (LastError != null)
ErrMessage = LastError.Message;
else
ErrMessage = "No Errors";
Response.Write("Last Error = " + ErrMessage);
59. How to do Caching in ASP?
A: <%@ OutputCache Duration="60" VaryByParam="None" %>
VaryByParam value Description
none One version of page cached (only raw GET)
* n versions of page cached based on query string and/or POST body
v1 n versions of page cached based on value of v1 variable in query string or POST body
v1;v2 n versions of page cached based on value of v1 and v2 variables in query string or POST body
60. <%@ OutputCache Duration="60" VaryByParam="none" %>
<%@ OutputCache Duration="60" VaryByParam="*" %>
<%@ OutputCache Duration="60" VaryByParam="name;age" %>
The OutputCache directive supports several other cache varying options
? VaryByHeader - maintain separate cache entry for header string changes (UserAgent, UserLanguage, etc.)
? VaryByControl - for user controls, maintain separate cache entry for properties of a user control
? VaryByCustom - can specify separate cache entries for browser types and version or provide a custom GetVaryByCustomString method in HttpApplicationderived class
61. What is the Global ASA(X) File?
62. Any alternative to avoid name collisions other then Namespaces.
A scenario that two namespaces named N1 and N2 are there both having the same class say A. now in another class i ve written
using N1;using N2;
and i am instantiating class A in this class. Then how will u avoid name collisions?
Ans: using alias
Eg: using MyAlias = MyCompany.Proj.Nested;
63. Which is the namespace used to write error message in event Log File?
64. What are the page level transaction and class level transaction?
65. What are different transaction options?
66. What is the namespace for encryption?
67. What is the difference between application and cache variables?
68. What is the difference between control and component?
69. You ve defined one page_load event in aspx page and same page_load event in code behind how will prog run?
70. Where would you use an IHttpModule, and what are the limitations of any approach you might take in implementing one?
71. Can you edit data in the Repeater control? Which template must you provide, in order to display data in a Repeater control? How can you provide an alternating color scheme in a Repeater control? What property must you set, and what method must you call in your code, in order to bind the data from some data source to the Repeater control?
72. What is the use of web.config? Difference between machine.config and Web.config?
ASP.NET configuration files are XML-based text files--each named web.config--that can appear in any directory on an ASP.NET
Web application server. Each web.config file applies configuration settings to the directory it is located in and to all
virtual child directories beneath it. Settings in child directories can optionally override or modify settings specified in
parent directories. The root configuration file--WinNT\Microsoft.NET\Framework\
default configuration settings for the entire machine. ASP.NET configures IIS to prevent direct browser access to web.config
files to ensure that their values cannot become public (attempts to access them will cause ASP.NET to return 403: Access
Forbidden).
At run time ASP.NET uses these web.config configuration files to hierarchically compute a unique collection of settings for
each incoming URL target request (these settings are calculated only once and then cached across subsequent requests; ASP.NET
automatically watches for file changes and will invalidate the cache if any of the configuration files change).
http://samples.gotdotnet.com/quickstart/aspplus/doc/configformat.aspx
73. What is the use of sessionstate tag in the web.config file?
Configuring session state: Session state features can be configured via the
74. What are the different modes for the sessionstates in the web.config file?
Off Indicates that session state is not enabled.
Inproc Indicates that session state is stored locally.
StateServer Indicates that session state is stored on a remote server.
SQLServer Indicates that session state is stored on the SQL Server.
75. What is smart navigation?
When a page is requested by an Internet Explorer 5 browser, or later, smart navigation enhances the user's experience of the page by performing the following:
? eliminating the flash caused by navigation.
? persisting the scroll position when moving from page to page.
? persisting element focus between navigations.
? retaining only the last page state in the browser's history.
Smart navigation is best used with ASP.NET pages that require frequent postbacks but with visual content that does not change dramatically on return. Consider this carefully when deciding whether to set this property to true.
Set the SmartNavigation attribute to true in the @ Page directive in the .aspx file. When the page is requested, the dynamically generated class sets this property.
76. In what order do the events of an ASPX page execute. As a developer is it important to undertsand these events?
77. How would you get ASP.NET running in Apache web servers - why would you even do this?
78. What tags do you need to add within the asp:datagrid tags to bind columns manually
79. What base class do all Web Forms inherit from?
System.Web.UI.Page
80. How can we create pie chart in asp.net?
81. Is it possible for me to change my aspx file extension to some other name?
Yes.
Open IIS->Default Website -> Properties
Select HomeDirectory tab
Click on configuration button
Click on add. Enter aspnet_isapi details (C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\aspnet_isapi.dll | GET,HEAD,POST,DEBUG)
Open machine.config(C:\WINDOWS\Microsoft.NET\Framework\v1.0.3705\CONFIG) & add new extension under
82. What is AutoEventWireup attribute for ?
WEBSERVICES AND REMOTING
1. What is a WebService and what is the underlying protocol used in it?Why Web Services?
Web Services are applications delivered as a service on the Web. Web services allow for programmatic access of business logic over the Web. Web services typically rely on XML-based protocols, messages, and interface descriptions for communication and access. Web services are designed to be used by other programs or applications rather than directly by end user. Programs invoking a Web service are called clients. SOAP over HTTP is the most commonly used protocol for invoking Web services.
There are three main uses of Web services.
1. Application integration Web services within an intranet are commonly used to integrate business applications running on disparate platforms. For example, a .NET client running on Windows 2000 can easily invoke a Java Web service running on a mainframe or Unix machine to retrieve data from a legacy application.
2. Business integration Web services allow trading partners to engage in e-business leveraging the existing Internet infrastructure. Organizations can send electronic purchase orders to suppliers and receive electronic invoices. Doing e-business with Web services means a low barrier to entry because Web services can be added to existing applications running on any platform without changing legacy code.
3. Commercial Web services focus on selling content and business services to clients over the Internet similar to familiar Web pages. Unlike Web pages, commercial Web services target applications not humans as their direct users. Continental Airlines exposes flight schedules and status Web services for travel Web sites and agencies to use in their applications. Like Web pages, commercial Web services are valuable only if they expose a valuable service or content. It would be very difficult to get customers to pay you for using a Web service that creates business charts with the customers? data. Customers would rather buy a charting component (e.g. COM or .NET component) and install it on the same machine as their application. On the other hand, it makes sense to sell real-time weather information or stock quotes as a Web service. Technology can help you add value to your services and explore new markets, but ultimately customers pay for contents and/or business services, not for technology
2. Are Web Services a replacement for other distributed computing platforms?
No. Web Services is just a new way of looking at existing implementation platforms.
3. In a Webservice, need to display 10 rows from a table. So DataReader or DataSet is best choice?
A: WebService will support only DataSet.
4. How to generate WebService proxy? What is SOAP, WSDL, UDDI and the concept behind Web Services? What are various components of WSDL? What is the use of WSDL.exe utility?
SOAP is an XML-based messaging framework specifically designed for exchanging formatted data across the Internet, for example using request and reply messages or sending entire documents. SOAP is simple, easy to use, and completely neutral with respect to operating system, programming language, or distributed computing platform.
After SOAP became available as a mechanism for exchanging XML messages among enterprises (or among disparate applications within the same enterprise), a better way was needed to describe the messages and how they are exchanged. The Web Services Description Language (WSDL) is a particular form of an XML Schema, developed by Microsoft and IBM for the purpose of defining the XML message, operation, and protocol mapping of a web service accessed using SOAP or other XML protocol. WSDL defines web services in terms of "endpoints" that operate on XML messages. The WSDL syntax allows both the messages and the operations on the messages to be defined abstractly, so they can be mapped to multiple physical implementations. The current WSDL spec describes how to map messages and operations to SOAP 1.1, HTTP GET/POST, and MIME. WSDL creates web service definitions by mapping a group of endpoints into a logical sequence of operations on XML messages. The same XML message can be mapped to multiple operations (or services) and bound to one or more communications protocols (using "ports").
The Universal Description, Discovery, and Integration (UDDI) framework defines a data model (in XML) and SOAP APIs for registration and searches on business information, including the web services a business exposes to the Internet. UDDI is an independent consortium of vendors, founded by Microsoft, IBM, and Ariba, for the purpose of developing an Internet standard for web service description registration and discovery. Microsoft, IBM, and Ariba also are hosting the initial deployment of a UDDI service, which is conceptually patterned after DNS (the Internet service that translates URLs into TCP addresses). UDDI uses a private agreement profile of SOAP (i.e. UDDI doesn't use the SOAP serialization format because it's not well suited to passing complete XML documents (it's aimed at RPC style interactions). The main idea is that businesses use the SOAP APIs to register themselves with UDDI, and other businesses search UDDI when they want to discover a trading partner, for example someone from whom they wish to procure sheet metal, bolts, or transistors. The information in UDDI is categorized according to industry type and geographical location, allowing UDDI consumers to search through lists of potentially matching businesses to find the specific one they want to contact. Once a specific business is chosen, another call to UDDI is made to obtain the specific contact information for that business. The contact information includes a pointer to the target business's WSDL or other XML schema file describing the web service that the target business publishes.
5. How to generate proxy class other than .net app and wsdl tool?
To access an XML Web service from a client application, you first add a Web reference, which is a reference to an XML Web service. When you create a Web reference, Visual Studio creates an XML Web service proxy class automatically and adds it to your project. This proxy class exposes the methods of the XML Web service and handles the marshalling of appropriate arguments back and forth between the XML Web service and your application. Visual Studio uses the Web Services Description Language (WSDL) to create the proxy.
To generate an XML Web service proxy class:
? From a command prompt, use Wsdl.exe to create a proxy class, specifying (at a minimum) the URL to an XML Web service or a service description, or the path to a saved service description.
Wsdl /language:language /protocol:protocol /namespace:myNameSpace /out:filename
/username:username /password:password /domain:domain
6. What is a proxy in web service? How do I use a proxy server when invoking a Web service?
7. asynchronous web service means?
8. What are the events fired when web service called?
9. How will do transaction in Web Services?
10. How does SOAP transport happen and what is the role of HTTP in it? How you can access a webservice using soap?
11. What are the different formatters can be used in both? Why?.. binary/soap
12. How you will protect / secure a web service?
For the most part, things that you do to secure a Web site can be used to secure a Web Service. If you need to encrypt the data exchange, you use Secure Sockets Layer (SSL) or a Virtual Private Network to keep the bits secure. For authentication, use HTTP Basic or Digest authentication with Microsoft® Windows® integration to figure out who the caller is.
these items cannot:
? Parse a SOAP request for valid values
? Authenticate access at the Web Method level (they can authenticate at the Web Service level)
? Stop reading a request as soon as it is recognized as invalid
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpcontransactionsupportinaspnetwebservices.asp
13. How will you expose/publish a webservice?
14. What is disco file?
15. What’s the attribute for webservice method? What is the namespace for creating webservice?
[WebMethod]
using System.Web;
using System.Web.Services;
16. What is Remoting?
The process of communication between different operating system processes, regardless of whether they are on the same computer. The .NET remoting system is an architecture designed to simplify communication between objects living in different application domains, whether on the same computer or not, and between different contexts, whether in the same application domain or not.
17. Difference between web services & remoting?
ASP.NET Web Services .NET Remoting
Protocol Can be accessed only over HTTP Can be accessed over any protocol (including TCP, HTTP, SMTP and so on)
State Management Web services work in a stateless environment Provide support for both stateful and stateless environments through Singleton and SingleCall objects
Type System Web services support only the datatypes defined in the XSD type system, limiting the number of objects that can be serialized. Using binary communication, .NET Remoting can provide support for rich type system
Interoperability Web services support interoperability across platforms, and are ideal for heterogeneous environments. .NET remoting requires the client be built using .NET, enforcing homogenous environment.
Reliability Highly reliable due to the fact that Web services are always hosted in IIS Can also take advantage of IIS for fault isolation. If IIS is not used, application needs to provide plumbing for ensuring the reliability of the application.
Extensibility Provides extensibility by allowing us to intercept the SOAP messages during the serialization and deserialization stages. Very extensible by allowing us to customize the different components of the .NET remoting framework.
Ease-of-Programming Easy-to-create and deploy. Complex to program.
18. Though both the .NET Remoting infrastructure and ASP.NET Web services can enable cross-process communication, each is designed to benefit a different target audience. ASP.NET Web services provide a simple programming model and a wide reach. .NET Remoting provides a more complex programming model and has a much narrower reach.
As explained before, the clear performance advantage provided by TCPChannel-remoting should make you think about using this channel whenever you can afford to do so. If you can create direct TCP connections from your clients to your server and if you need to support only the .NET platform, you should go for this channel. If you are going to go cross-platform or you have the requirement of supporting SOAP via HTTP, you should definitely go for ASP.NET Web services.
Both the .NET remoting and ASP.NET Web services are powerful technologies that provide a suitable framework for developing distributed applications. It is important to understand how both technologies work and then choose the one that is right for your application. For applications that require interoperability and must function over public networks, Web services are probably the best bet. For those that require communications with other .NET components and where performance is a key priority, .NET Remoting is the best choice. In short, use Web services when you need to send and receive data from different computing platforms, use .NET Remoting when sending and receiving data between .NET applications. In some architectural scenarios, you might also be able to use.NET Remoting in conjunction with ASP.NET Web services and take advantage of the best of both worlds.
The Key difference between ASP.NET webservices and .NET Remoting is how they serialize data into messages and the format they choose for metadata. ASP.NET uses XML serializer for serializing or Marshalling. And XSD is used for Metadata. .NET Remoting relies on System.Runtime.Serialization.Formatter.Binary and System.Runtime.Serialization.SOAPFormatter and relies on .NET CLR Runtime assemblies for metadata.
19.
20. Can you pass SOAP messages through remoting?
21. CAO and SAO.
Client Activated objects are those remote objects whose Lifetime is directly Controlled by the client. This is in direct contrast to SAO. Where the server, not the client has complete control over the lifetime of the objects.
Client activated objects are instantiated on the server as soon as the client request the object to be created. Unlike as SAO a CAO doesn’t delay the object creation until the first method is called on the object. (In SAO the object is instantiated when the client calls the method on the object)
22. singleton and singlecall.
Singleton types never have more than one instance at any one time. If an instance exists, all client requests are serviced by that instance.
Single Call types always have one instance per client request. The next method invocation will be serviced by a different server instance, even if the previous instance has not yet been recycled by the system.
23. What is Asynchronous Web Services?
24. Web Client class and its methods?
25. Flow of remoting?
26. What is the use of trace utility?
Using the SOAP Trace Utility
The Microsoft® Simple Object Access Protocol (SOAP) Toolkit 2.0 includes a TCP/IP trace utility, MSSOAPT.EXE. You use this trace utility to view the SOAP messages sent by HTTP between a SOAP client and a service on the server.
Using the Trace Utility on the Server
To see all of a service's messages received from and sent to all clients, perform the following steps on the server.
0. On the server, open the Web Services Description Language (WSDL) file.
1. In the WSDL file, locate the
2. Run MSSOAPT.exe.
3. On the File menu, point to New, and either click Formatted Trace (if you don't want to see HTTP headers) or click Unformatted Trace (if you do want to see HTTP headers).
4. In the Trace Setup dialog box, click OK to accept the default values.
Using the Trace Utility on the Client
To see all messages sent to and received from a service, do the following steps on the client.
5. Copy the WSDL file from the server to the client.
6. Modify location attribute of the
7. On the client, run MSSOPT.exe.
8. On the File menu, point to New, and either click Formatted Trace (if you don't want to see HTTP headers) or click Unformatted Trace (if you do want to see HTTP headers).
9. In the Destination host box, enter the host specified in Step 2.
10. In the Destination port box, enter the port specified in Step 2.
11. Click OK.
COM
1. Interop Services?
The common language runtime provides two mechanisms for interoperating with unmanaged code:
? Platform invoke, which enables managed code to call functions exported from an unmanaged library.
? COM interop, which enables managed code to interact with COM objects through interfaces.
Both platform invoke and COM interop use interop marshaling to accurately move method arguments between caller and callee and back, if required.
2. How does u handle this COM components developed in other programming languages in .NET?
3. What is RCW (Runtime Callable Wrappers)?
The common language runtime exposes COM objects through a proxy called the runtime callable wrapper (RCW). Although the RCW appears to be an ordinary object to .NET clients, its primary function is to marshal calls between a .NET client and a COM object.
4. What is CCW (COM Callable Wrapper)
A proxy object generated by the common language runtime so that existing COM applications can use managed classes, including .NET Framework classes, transparently.
5. How CCW and RCW is working?
**
6. How will you register com+ services?
The .NET Framework SDK provides the .NET Framework Services Installation Tool (Regsvcs.exe - a command-line tool) to manually register an assembly containing serviced components. You can also access these registration features programmatically with the System.EnterpriseServicesRegistrationHelper class by creating an instance of class RegistrationHelper and using the method InstallAssembly
7. What is use of ContextUtil class?
ContextUtil is the preferred class to use for obtaining COM+ context information.
8. What is the new three features of COM+ services, which are not there in COM (MTS)?
**
9. Is the COM architecture same as .Net architecture? What is the difference between them?
**
10. Can we copy a COM dll to GAC folder?
**
11. What is Pinvoke?
Platform invoke is a service that enables managed code to call unmanaged functions implemented in dynamic-link libraries (DLLs), such as those in the Win32 API. It locates and invokes an exported function and marshals its arguments (integers, strings, arrays, structures, and so on) across the interoperation boundary as needed.
12. Is it true that COM objects no longer need to be registered on the server?
Answer: Yes and No. Legacy COM objects still need to be registered on the server before they can be used. COM developed using the new .NET Framework will not need to be registered. Developers will be able to auto-register these objects just by placing them in the 'bin' folder of the application.
13. Can .NET Framework components use the features of Component Services?
Answer: Yes, you can use the features and functions of Component Services from a .NET Framework component. http://msdn.microsoft.com/library/techart/Pahlcompserv.htm
XML
1. Explain the concept of data island?
2. How to use XML DOM model on client side using JavaScript.
3. What are the ways to create a tree view control using XML, XSL & JavaScript?
4. Questions on XPathNavigator, and the other classes in System.XML Namespace?
5. What is Use of Template in XSL?
6. What is “Well Formed XML” and “Valid XML”
7. How you will do SubString in XSL
8. Can we do sorting in XSL ? how do you deal sorting columns dynamically in XML.
9. What is “Async” property of XML Means ?
10. What is XPath Query ?
11. Difference Between Element and Node.
12. What is CDATA Section.
13. DOM & SAX parsers explanation and difference
14. What is GetElementbyname method will do?
15. What is selectnode method will give?
16. What is valid xml document? What a well formed xml document?
17. What is the Difference between XmlDocument and XmlDataDocument?
18. Explain what a DiffGram is, and a good use for one?
A DiffGram is an XML format that is used to identify current and original versions of data elements. When sending and retrieving a DataSet from an XML Web service, the DiffGram format is implicitly used.
The DataSet uses the DiffGram format to load and persist its contents, and to serialize its contents for transport across a network connection. When a DataSet is written as a DiffGram, it populates the DiffGram with all the necessary information to accurately recreate the contents, though not the schema, of the DataSet, including column values from both the Original and Current row versions, row error information, and row order.
DiffGram Format
The DiffGram format is divided into three sections: the current data, the original (or "before") data, and an errors section, as shown in the following example.
The DiffGram format consists of the following blocks of data:
The name of this element, DataInstance, is used for explanation purposes in this documentation. A DataInstance element represents a DataSet or a row of a DataTable. Instead of DataInstance, the element would contain the name of the DataSet or DataTable. This block of the DiffGram format contains the current data, whether it has been modified or not. An element, or row, that has been modified is identified with the diffgr:hasChanges annotation.
This block of the DiffGram format contains the original version of a row. Elements in this block are matched to elements in the DataInstance block using the diffgr:id annotation.
This block of the DiffGram format contains error information for a particular row in the DataInstance block. Elements in this block are matched to elements in the DataInstance block using the diffgr:id annotation.
19. If I replace my Sqlserver with XML files and how about handling the same?
20. Write syntax to serialize class using XML Serializer?
IIS
1. In which process does IIS runs (was asking about the EXE file)
inetinfo.exe is the Microsoft IIS server running, handling ASP.NET requests among other things. When an ASP.NET request is received (usually a file with .aspx extension), the ISAPI filter aspnet_isapi.dll takes care of it by passing the request to the actual worker process aspnet_wp.exe.
2. Where are the IIS log files stored?
C:\WINDOWS\system32\Logfiles\W3SVC1
OR
c:\winnt\system32\LogFiles\W3SVC1
3. What are the different IIS authentication modes in IIS 5.0 and Explain? Difference between basic and digest authentication modes?
IIS provides a variety of authentication schemes:
? Anonymous (enabled by default)
? Basic
? Digest
? Integrated Windows authentication (enabled by default)
? Client Certificate Mapping
Anonymous
Anonymous authentication gives users access to the public areas of your Web site without prompting them for a user name or password. Although listed as an authentication scheme, it is not technically performing any client authentication because the client is not required to supply any credentials. Instead, IIS provides stored credentials to Windows using a special user account, IUSR_machinename. By default, IIS controls the password for this account. Whether or not IIS controls the password affects the permissions the anonymous user has. When IIS controls the password, a sub authentication DLL (iissuba.dll) authenticates the user using a network logon. The function of this DLL is to validate the password supplied by IIS and to inform Windows that the password is valid, thereby authenticating the client. However, it does not actually provide a password to Windows. When IIS does not control the password, IIS calls the LogonUser() API in Windows and provides the account name, password and domain name to log on the user using a local logon. After the logon, IIS caches the security token and impersonates the account. A local logon makes it possible for the anonymous user to access network resources, whereas a network logon does not.
Basic Authentication
IIS Basic authentication as an implementation of the basic authentication scheme found in section 11 of the HTTP 1.0 specification.
As the specification makes clear, this method is, in and of itself, non-secure. The reason is that Basic authentication assumes a trusted connection between client and server. Thus, the username and password are transmitted in clear text. More specifically, they are transmitted using Base64 encoding, which is trivially easy to decode. This makes Basic authentication the wrong choice to use over a public network on its own.
Basic Authentication is a long-standing standard supported by nearly all browsers. It also imposes no special requirements on the server side -- users can authenticate against any NT domain, or even against accounts on the local machine. With SSL to shelter the security credentials while they are in transmission, you have an authentication solution that is both highly secure and quite flexible.
Digest Authentication
The Digest authentication option was added in Windows 2000 and IIS 5.0. Like Basic authentication, this is an implementation of a technique suggested by Web standards, namely RFC 2069 (superceded by RFC 2617).
Digest authentication also uses a challenge/response model, but it is much more secure than Basic authentication (when used without SSL). It achieves this greater security not by encrypting the secret (the password) before sending it, but rather by following a different design pattern -- one that does not require the client to transmit the password over the wire at all.
Instead of sending the password itself, the client transmits a one-way message digest (a checksum) of the user's password, using (by default) the MD5 algorithm. The server then fetches the password for that user from a Windows 2000 Domain Controller, reruns the checksum algorithm on it, and compares the two digests. If they match, the server knows that the client knows the correct password, even though the password itself was never sent. (If you have ever wondered what the default ISAPI filter "md5filt" that is installed with IIS 5.0 is used for, now you know.
Integrated Windows Authentication
Integrated Windows authentication (formerly known as NTLM authentication and Windows NT Challenge/Response authentication) can use either NTLM or Kerberos V5 authentication and only works with Internet Explorer 2.0 and later.
When Internet Explorer attempts to access a protected resource, IIS sends two WWW-Authenticate headers, Negotiate and NTLM.
? If Internet Explorer recognizes the Negotiate header, it will choose it because it is listed first. When using Negotiate, the browser will return information for both NTLM and Kerberos. At the server, IIS will use Kerberos if both the client (Internet Explorer 5.0 and later) and server (IIS 5.0 and later) are running Windows 2000 and later, and both are members of the same domain or trusted domains. Otherwise, the server will default to using NTLM.
? If Internet Explorer does not understand Negotiate, it will use NTLM.
So, which mechanism is used depends upon a negotiation between Internet Explorer and IIS.
When used in conjunction with Kerberos v5 authentication, IIS can delegate security credentials among computers running Windows 2000 and later that are trusted and configured for delegation. Delegation enables remote access of resources on behalf of the delegated user.
Integrated Windows authentication is the best authentication scheme in an intranet environment where users have Windows domain accounts, especially when using Kerberos. Integrated Windows authentication, like digest authentication, does not pass the user's password across the network. Instead, a hashed value is exchanged.
Client Certificate Mapping
A certificate is a digitally signed statement that contains information about an entity and the entity's public key, thus binding these two pieces of information together. A trusted organization (or entity) called a Certification Authority (CA) issues a certificate after the CA verifies that the entity is who it says it is. Certificates can contain different types of data. For example, an X.509 certificate includes the format of the certificate, the serial number of the certificate, the algorithm used to sign the certificate, the name of the CA that issued the certificate, the name and public key of the entity requesting the certificate, and the CA's signature. X.509 client certificates simplify authentication for larger user bases because they do not rely on a centralized account database. You can verify a certificate simply by examining the certificate.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vsent7/html/vxconIISAuthentication.asp
4. How to configure the sites in Web server (IIS)?
5. Advantages in IIS 6.0?
http://www.microsoft.com/windowsserver2003/iis/evaluation/features/default.mspx
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/prodtechnol/windowsserver2003/proddocs/datacenter/gs_whatschanged.asp
6. IIS Isolation Levels?
Internet Information Server introduced the notion "Isolation Level", which is also present in IIS4 under a different name. IIS5 supports three isolation levels, that you can set from the Home Directory tab of the site's Properties dialog:
? Low (IIS Process): ASP pages run in INetInfo.Exe, the main IIS process, therefore they are executed in-process. This is the fastest setting, and is the default under IIS4. The problem is that if ASP crashes, IIS crashes as well and must be restarted (IIS5 has a reliable restart feature that automatically restarts a server when a fatal error occurs).
? Medium (Pooled): In this case ASP runs in a different process, which makes this setting more reliable: if ASP crashes IIS won't. All the ASP applications at the Medium isolation level share the same process, so you can have a web site running with just two processes (IIS and ASP process). IIS5 is the first Internet Information Server version that supports this setting, which is also the default setting when you create an IIS5 application. Note that an ASP application that runs at this level is run under COM+, so it's hosted in DLLHOST.EXE (and you can see this executable in the Task Manager).
? High (Isolated): Each ASP application runs out-process in its own process space, therefore if an ASP application crashes, neither IIS nor any other ASP application will be affected. The downside is that you consume more memory and resources if the server hosts many ASP applications. Both IIS4 and IIS5 supports this setting: under IIS4 this process runs inside MTS.EXE, while under IIS5 it runs inside DLLHOST.EXE.
When selecting an isolation level for your ASP application, keep in mind that out-process settings - that is, Medium and High - are less efficient than in-process (Low). However, out-process communication has been vastly improved under IIS5, and in fact IIS5's Medium isolation level often deliver better results than IIS4's Low isolation. In practice, you shouldn't set the Low isolation level for an IIS5 application unless you really need to serve hundreds pages per second.
SQL
T-SQL Optimization Tips
? Use views and stored procedures instead of heavy-duty queries.
This can reduce network traffic, because your client will send to server only stored procedure or view name (perhaps with some parameters) instead of large heavy-duty queries text. This can be used to facilitate permission management also, because you can restrict user access to table columns they should not see.
? Try to use constraints instead of triggers, whenever possible.
Constraints are much more efficient than triggers and can boost performance. So, you should use constraints instead of triggers, whenever possible.
? Use table variables instead of temporary tables.
Table variables require less locking and logging resources than temporary tables, so table variables should be used whenever possible. The table variables are available in SQL Server 2000 only.
? Try to use UNION ALL statement instead of UNION, whenever possible.
The UNION ALL statement is much faster than UNION, because UNION ALL statement does not look for duplicate rows, and UNION statement does look for duplicate rows, whether or not they exist.
? Try to avoid using the DISTINCT clause, whenever possible.
Because using the DISTINCT clause will result in some performance degradation, you should use this clause only when it is necessary.
? Try to avoid using SQL Server cursors, whenever possible.
SQL Server cursors can result in some performance degradation in comparison with select statements. Try to use correlated sub-query or derived tables, if you need to perform row-by-row operations.
? Try to avoid the HAVING clause, whenever possible.
The HAVING clause is used to restrict the result set returned by the GROUP BY clause. When you use GROUP BY with the HAVING clause, the GROUP BY clause divides the rows into sets of grouped rows and aggregates their values, and then the HAVING clause eliminates undesired aggregated groups. In many cases, you can write your select statement so, that it will contain only WHERE and GROUP BY clauses without HAVING clause. This can improve the performance of your query.
? If you need to return the total table's row count, you can use alternative way instead of SELECT COUNT(*) statement.
Because SELECT COUNT(*) statement make a full table scan to return the total table's row count, it can take very many time for the large table. There is another way to determine the total row count in a table. You can use sysindexes system table, in this case. There is ROWS column in the sysindexes table. This column contains the total row count for each table in your database. So, you can use the following select statement instead of SELECT COUNT(*): SELECT rows FROM sysindexes WHERE id = OBJECT_ID('table_name') AND indid < command1="print '?' DBCC DBREINDEX ('?')"> 1))
4. Select the details of 3 max salaried employees from employee table.
SELECT TOP 3 empid, salary
FROM employee
ORDER BY salary DESC
5. Display all managers from the table. (manager id is same as emp id)
SELECT empname
FROM employee
WHERE (empid IN
(SELECT DISTINCT mgrid
FROM employee))
6. Write a Select statement to list the Employee Name, Manager Name under a particular manager?
SELECT e1.empname AS EmpName, e2.empname AS ManagerName
FROM Employee e1 INNER JOIN
Employee e2 ON e1.mgrid = e2.empid
ORDER BY e2.mgrid
7. 2 tables emp and phone.
emp fields are - empid, name
Ph fields are - empid, ph (office, mobile, home). Select all employees who doesn't have any ph nos.
SELECT *
FROM employee LEFT OUTER JOIN
phone ON employee.empid = phone.empid
WHERE (phone.office IS NULL OR phone.office = ' ')
AND (phone.mobile IS NULL OR phone.mobile = ' ')
AND (phone.home IS NULL OR phone.home = ' ')
8. Find employee who is living in more than one city.
Two Tables:
Emp City
Empid
empName
Salary Empid
City
9. SELECT empname, fname, lname
FROM employee
WHERE (empid IN
(SELECT empid
FROM city
GROUP BY empid
HAVING COUNT(empid) > 1))
10. Find all employees who is living in the same city. (table is same as above)
SELECT fname
FROM employee
WHERE (empid IN
(SELECT empid
FROM city a
WHERE city IN
(SELECT city
FROM city b
GROUP BY city
HAVING COUNT(city) > 1)))
11. There is a table named MovieTable with three columns - moviename, person and role. Write a query which gets the movie details where Mr. Amitabh and Mr. Vinod acted and their role is actor.
SELECT DISTINCT m1.moviename
FROM MovieTable m1 INNER JOIN
MovieTable m2 ON m1.moviename = m2.moviename
WHERE (m1.person = 'amitabh' AND m2.person = 'vinod' OR
m2.person = 'amitabh' AND m1.person = 'vinod') AND (m1.role = 'actor') AND (m2.role = 'actor')
ORDER BY m1.moviename
12. There are two employee tables named emp1 and emp2. Both contains same structure (salary details). But Emp2 salary details are incorrect and emp1 salary details are correct. So, write a query which corrects salary details of the table emp2
update a set a.sal=b.sal from emp1 a, emp2 b where a.empid=b.empid
13. Given a Table named “Students” which contains studentid, subjectid and marks. Where there are 10 subjects and 50 students. Write a Query to find out the Maximum marks obtained in each subject.
14. In this same tables now write a SQL Query to get the studentid also to combine with previous results.
15. Three tables – student , course, marks – how do go at finding name of the students who got max marks in the diff courses.
SELECT student.name, course.name AS coursename, marks.sid, marks.mark
FROM marks INNER JOIN
student ON marks.sid = student.sid INNER JOIN
course ON marks.cid = course.cid
WHERE (marks.mark =
(SELECT MAX(Mark)
FROM Marks MaxMark
WHERE MaxMark.cID = Marks.cID))
16. There is a table day_temp which has three columns dayid, day and temperature. How do I write a query to get the difference of temperature among each other for seven days of a week?
SELECT a.dayid, a.dday, a.tempe, a.tempe - b.tempe AS Difference
FROM day_temp a INNER JOIN
day_temp b ON a.dayid = b.dayid + 1
OR
Select a.day, a.degree-b.degree from temperature a, temperature b where a.id=b.id+1
17. There is a table which contains the names like this. a1, a2, a3, a3, a4, a1, a1, a2 and their salaries. Write a query to get grand total salary, and total salaries of individual employees in one query.
SELECT empid, SUM(salary) AS salary
FROM employee
GROUP BY empid WITH ROLLUP
ORDER BY empid
18. How to know how many tables contains empno as a column in a database?
SELECT COUNT(*) AS Counter
FROM syscolumns
WHERE (name = 'empno')
19. Find duplicate rows in a table? OR I have a table with one column which has many records which are not distinct. I need to find the distinct values from that column and number of times it’s repeated.
SELECT sid, mark, COUNT(*) AS Counter
FROM marks
GROUP BY sid, mark
HAVING (COUNT(*) > 1)
20. How to delete the rows which are duplicate (don’t delete both duplicate records).
SET ROWCOUNT 1
DELETE yourtable
FROM yourtable a
WHERE (SELECT COUNT(*) FROM yourtable b WHERE b.name1 = a.name1 AND b.age1 = a.age1) > 1
WHILE @@rowcount > 0
DELETE yourtable
FROM yourtable a
WHERE (SELECT COUNT(*) FROM yourtable b WHERE b.name1 = a.name1 AND b.age1 = a.age1) > 1
SET ROWCOUNT 0
21. How to find 6th highest salary
SELECT TOP 1 salary
FROM (SELECT DISTINCT TOP 6 salary
FROM employee
ORDER BY salary DESC) a
ORDER BY salary
22. Find top salary among two tables
SELECT TOP 1 sal
FROM (SELECT MAX(sal) AS sal
FROM sal1
UNION
SELECT MAX(sal) AS sal
FROM sal2) a
ORDER BY sal DESC
23. Write a query to convert all the letters in a word to upper case
SELECT UPPER('test')
24. Write a query to round up the values of a number. For example even if the user enters 7.1 it should be rounded up to 8.
SELECT CEILING (7.1)
25. Write a SQL Query to find first day of month?
SELECT DATENAME(dw, DATEADD(dd, - DATEPART(dd, GETDATE()) + 1, GETDATE())) AS FirstDay
Datepart Abbreviations
year yy, yyyy
quarter qq, q
month mm, m
dayofyear dy, y
day dd, d
week wk, ww
weekday dw
hour hh
minute mi, n
second ss, s
millisecond ms
26. Table A contains column1 which is primary key and has 2 values (1, 2) and Table B contains column1 which is primary key and has 2 values (2, 3). Write a query which returns the values that are not common for the tables and the query should return one column with 2 records.
SELECT tbla.a
FROM tbla, tblb
WHERE tbla.a <>
(SELECT tblb.a
FROM tbla, tblb
WHERE tbla.a = tblb.a)
UNION
SELECT tblb.a
FROM tbla, tblb
WHERE tblb.a <>
(SELECT tbla.a
FROM tbla, tblb
WHERE tbla.a = tblb.a)
OR (better approach)
SELECT a
FROM tbla
WHERE a NOT IN
(SELECT a
FROM tblb)
UNION ALL
SELECT a
FROM tblb
WHERE a NOT IN
(SELECT a
FROM tbla)
27. There are 3 tables Titles, Authors and Title-Authors (check PUBS db). Write the query to get the author name and the number of books written by that author, the result should start from the author who has written the maximum number of books and end with the author who has written the minimum number of books.
SELECT authors.au_lname, COUNT(*) AS BooksCount
FROM authors INNER JOIN
titleauthor ON authors.au_id = titleauthor.au_id INNER JOIN
titles ON titles.title_id = titleauthor.title_id
GROUP BY authors.au_lname
ORDER BY BooksCount DESC
28.
UPDATE emp_master
SET emp_sal =
CASE
WHEN emp_sal > 0 AND emp_sal <= 20000 THEN (emp_sal * 1.01) WHEN emp_sal > 20000 THEN (emp_sal * 1.02)
END
29. List all products with total quantity ordered, if quantity ordered is null show it as 0.
SELECT name, CASE WHEN SUM(qty) IS NULL THEN 0 WHEN SUM(qty) > 0 THEN SUM(qty) END AS tot
FROM [order] RIGHT OUTER JOIN
product ON [order].prodid = product.prodid
GROUP BY name
Result:
coke 60
mirinda 0
pepsi 10
30. ANY, SOME, or ALL?
ALL means greater than every value--in other words, greater than the maximum value. For example, >ALL (1, 2, 3) means greater than 3.
ANY means greater than at least one value, that is, greater than the minimum. So >ANY (1, 2, 3) means greater than 1. SOME is an SQL-92 standard equivalent for ANY.
31. IN & = (difference in correlated sub query)
INDEXES
1. What is Index? It’s purpose?
Indexes in databases are similar to indexes in books. In a database, an index allows the database program to find data in a table without scanning the entire table. An index in a database is a list of values in a table with the storage locations of rows in the table that contain each value. Indexes can be created on either a single column or a combination of columns in a table and are implemented in the form of B-trees. An index contains an entry with one or more columns (the search key) from each row in a table. A B-tree is sorted on the search key, and can be searched efficiently on any leading subset of the search key. For example, an index on columns A, B, C can be searched efficiently on A, on A, B, and A, B, C.
2. Explain about Clustered and non clustered index? How to choose between a Clustered Index and a Non-Clustered Index?
There are clustered and nonclustered indexes. A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.
A nonclustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf nodes of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.
Consider using a clustered index for:
o Columns that contain a large number of distinct values.
o Queries that return a range of values using operators such as BETWEEN, >, >=, <, and <=. o Columns that are accessed sequentially. o Queries that return large result sets. Non-clustered indexes have the same B-tree structure as clustered indexes, with two significant differences: o The data rows are not sorted and stored in order based on their non-clustered keys. o The leaf layer of a non-clustered index does not consist of the data pages. Instead, the leaf nodes contain index rows. Each index row contains the non-clustered key value and one or more row locators that point to the data row (or rows if the index is not unique) having the key value. o Per table only 249 non clustered indexes. 3. Disadvantage of index? Every index increases the time in takes to perform INSERTS, UPDATES and DELETES, so the number of indexes should not be very much. 4. Given a scenario that I have a 10 Clustered Index in a Table to all their 10 Columns. What are the advantages and disadvantages? A: Only 1 clustered index is possible. 5. How can I enforce to use particular index? You can use index hint (index=
SELECT au_lname FROM authors (index=aunmind)
6. What is Index Tuning?
One of the hardest tasks facing database administrators is the selection of appropriate columns for non-clustered indexes. You should consider creating non-clustered indexes on any columns that are frequently referenced in the WHERE clauses of SQL statements. Other good candidates are columns referenced by JOIN and GROUP BY operations.
You may wish to also consider creating non-clustered indexes that cover all of the columns used by certain frequently issued queries. These queries are referred to as “covered queries” and experience excellent performance gains.
Index Tuning is the process of finding appropriate column for non-clustered indexes.
SQL Server provides a wonderful facility known as the Index Tuning Wizard which greatly enhances the index selection process.
7. Difference between Index defrag and Index rebuild?
When you create an index in the database, the index information used by queries is stored in index pages. The sequential index pages are chained together by pointers from one page to the next. When changes are made to the data that affect the index, the information in the index can become scattered in the database. Rebuilding an index reorganizes the storage of the index data (and table data in the case of a clustered index) to remove fragmentation. This can improve disk performance by reducing the number of page reads required to obtain the requested data
DBCC INDEXDEFRAG - Defragments clustered and secondary indexes of the specified table or view.
**
8. What is sorting and what is the difference between sorting & clustered indexes?
The ORDER BY clause sorts query results by one or more columns up to 8,060 bytes. This will happen by the time when we retrieve data from database. Clustered indexes physically sorting data, while inserting/updating the table.
9. What are statistics, under what circumstances they go out of date, how do you update them?
Statistics determine the selectivity of the indexes. If an indexed column has unique values then the selectivity of that index is more, as opposed to an index with non-unique values. Query optimizer uses these indexes in determining whether to choose an index or not while executing a query.
Some situations under which you should update statistics:
1) If there is significant change in the key values in the index
2) If a large amount of data in an indexed column has been added, changed, or removed (that is, if the distribution of key values has changed), or the table has been truncated using the TRUNCATE TABLE statement and then repopulated
3) Database is upgraded from a previous version
10. What is fillfactor? What is the use of it ? What happens when we ignore it? When you should use low fill factor?
When you create a clustered index, the data in the table is stored in the data pages of the database according to the order of the values in the indexed columns. When new rows of data are inserted into the table or the values in the indexed columns are changed, Microsoft® SQL Server™ 2000 may have to reorganize the storage of the data in the table to make room for the new row and maintain the ordered storage of the data. This also applies to nonclustered indexes. When data is added or changed, SQL Server may have to reorganize the storage of the data in the nonclustered index pages. When a new row is added to a full index page, SQL Server moves approximately half the rows to a new page to make room for the new row. This reorganization is known as a page split. Page splitting can impair performance and fragment the storage of the data in a table.
When creating an index, you can specify a fill factor to leave extra gaps and reserve a percentage of free space on each leaf level page of the index to accommodate future expansion in the storage of the table's data and reduce the potential for page splits. The fill factor value is a percentage from 0 to 100 that specifies how much to fill the data pages after the index is created. A value of 100 means the pages will be full and will take the least amount of storage space. This setting should be used only when there will be no changes to the data, for example, on a read-only table. A lower value leaves more empty space on the data pages, which reduces the need to split data pages as indexes grow but requires more storage space. This setting is more appropriate when there will be changes to the data in the table.
DATA TYPES
11. What are the data types in SQL
bigint Binary bit char cursor
datetime Decimal float image int
money Nchar ntext nvarchar real
smalldatetime Smallint smallmoney text timestamp
tinyint Varbinary Varchar uniqueidentifier
12. Difference between char and nvarchar / char and varchar data-type?
char[(n)] - Fixed-length non-Unicode character data with length of n bytes. n must be a value from 1 through 8,000. Storage size is n bytes. The SQL-92 synonym for char is character.
nvarchar(n) - Variable-length Unicode character data of n characters. n must be a value from 1 through 4,000. Storage size, in bytes, is two times the number of characters entered. The data entered can be 0 characters in length. The SQL-92 synonyms for nvarchar are national char varying and national character varying.
varchar[(n)] - Variable-length non-Unicode character data with length of n bytes. n must be a value from 1 through 8,000. Storage size is the actual length in bytes of the data entered, not n bytes. The data entered can be 0 characters in length. The SQL-92 synonyms for varchar are char varying or character varying.
13. GUID datasize?
128bit
14. How GUID becoming unique across machines?
To ensure uniqueness across machines, the ID of the network card is used (among others) to compute the number.
15. What is the difference between text and image data type?
Text and image. Use text for character data if you need to store more than 255 characters in SQL Server 6.5, or more than 8000 in SQL Server 7.0. Use image for binary large objects (BLOBs) such as digital images. With text and image data types, the data is not stored in the row, so the limit of the page size does not apply.All that is stored in the row is a pointer to the database pages that contain the data.Individual text, ntext, and image values can be a maximum of 2-GB, which is too long to store in a single data row.
JOINS
16. What are joins?
Sometimes we have to select data from two or more tables to make our result complete. We have to perform a join.
17. How many types of Joins?
Joins can be categorized as:
? Inner joins (the typical join operation, which uses some comparison operator like = or <>). These include equi-joins and natural joins.
Inner joins use a comparison operator to match rows from two tables based on the values in common columns from each table. For example, retrieving all rows where the student identification number is the same in both the students and courses tables.
? Outer joins. Outer joins can be a left, a right, or full outer join.
Outer joins are specified with one of the following sets of keywords when they are specified in the FROM clause:
? LEFT JOIN or LEFT OUTER JOIN -The result set of a left outer join includes all the rows from the left table specified in the LEFT OUTER clause, not just the ones in which the joined columns match. When a row in the left table has no matching rows in the right table, the associated result set row contains null values for all select list columns coming from the right table.
? RIGHT JOIN or RIGHT OUTER JOIN - A right outer join is the reverse of a left outer join. All rows from the right table are returned. Null values are returned for the left table any time a right table row has no matching row in the left table.
? FULL JOIN or FULL OUTER JOIN - A full outer join returns all rows in both the left and right tables. Any time a row has no match in the other table, the select list columns from the other table contain null values. When there is a match between the tables, the entire result set row contains data values from the base tables.
? Cross joins - Cross joins return all rows from the left table, each row from the left table is combined with all rows from the right table. Cross joins are also called Cartesian products. (A Cartesian join will get you a Cartesian product. A Cartesian join is when you join every row of one table to every row of another table. You can also get one by joining every row of a table to every row of itself.)
18. What is self join?
A table can be joined to itself in a self-join.
19. What are the differences between UNION and JOINS?
A join selects columns from 2 or more tables. A union selects rows.
20. Can I improve performance by using the ANSI-style joins instead of the old-style joins?
Code Example 1:
select o.name, i.name
from sysobjects o, sysindexes i
where o.id = i.id
Code Example 2:
select o.name, i.name
from sysobjects o inner join sysindexes i
on o.id = i.id
You will not get any performance gain by switching to the ANSI-style JOIN syntax.
Using the ANSI-JOIN syntax gives you an important advantage: Because the join logic is cleanly separated from the filtering criteria, you can understand the query logic more quickly.
The SQL Server old-style JOIN executes the filtering conditions before executing the joins, whereas the ANSI-style JOIN reverses this procedure (join logic precedes filtering).
Perhaps the most compelling argument for switching to the ANSI-style JOIN is that Microsoft has explicitly stated that SQL Server will not support the old-style OUTER JOIN syntax indefinitely. Another important consideration is that the ANSI-style JOIN supports query constructions that the old-style JOIN syntax does not support.
21. What is derived table?
Derived tables are SELECT statements in the FROM clause referred to by an alias or a user-specified name. The result set of the SELECT in the FROM clause forms a table used by the outer SELECT statement. For example, this SELECT uses a derived table to find if any store carries all book titles in the pubs database:
SELECT ST.stor_id, ST.stor_name
FROM stores AS ST,
(SELECT stor_id, COUNT(DISTINCT title_id) AS title_count
FROM sales
GROUP BY stor_id
) AS SA
WHERE ST.stor_id = SA.stor_id
AND SA.title_count = (SELECT COUNT(*) FROM titles)
locks
1. What are locks?
Microsoft® SQL Server™ 2000 uses locking to ensure transactional integrity and database consistency. Locking prevents users from reading data being changed by other users, and prevents multiple users from changing the same data at the same time. If locking is not used, data within the database may become logically incorrect, and queries executed against that data may produce unexpected results.
2. What are the different types of locks?
SQL Server uses these resource lock modes.
Lock mode Description
Shared (S) Used for operations that do not change or update data (read-only operations), such as a SELECT statement.
Update (U) Used on resources that can be updated. Prevents a common form of deadlock that occurs when multiple sessions are reading, locking, and potentially updating resources later.
Exclusive (X) Used for data-modification operations, such as INSERT, UPDATE, or DELETE. Ensures that multiple updates cannot be made to the same resource at the same time.
Intent Used to establish a lock hierarchy. The types of intent locks are: intent shared (IS), intent exclusive (IX), and shared with intent exclusive (SIX).
Schema Used when an operation dependent on the schema of a table is executing. The types of schema locks are: schema modification (Sch-M) and schema stability (Sch-S).
Bulk Update (BU) Used when bulk-copying data into a table and the TABLOCK hint is specified.
3. What is a dead lock? Give a practical sample? How you can minimize the deadlock situation? What is a deadlock and what is a live lock? How will you go about resolving deadlocks?
Deadlock is a situation when two processes, each having a lock on one piece of data, attempt to acquire a lock on the other's piece. Each process would wait indefinitely for the other to release the lock, unless one of the user processes is terminated. SQL Server detects deadlocks and terminates one user's process.
A livelock is one, where a request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. SQL Server detects the situation after four denials and refuses further shared locks. (A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely.)
4. What is isolation level?
An isolation level determines the degree of isolation of data between concurrent transactions. The default SQL Server isolation level is Read Committed. A lower isolation level increases concurrency, but at the expense of data correctness. Conversely, a higher isolation level ensures that data is correct, but can affect concurrency negatively. The isolation level required by an application determines the locking behavior SQL Server uses.
SQL-92 defines the following isolation levels, all of which are supported by SQL Server:
? Read uncommitted (the lowest level where transactions are isolated only enough to ensure that physically corrupt data is not read).
? Read committed (SQL Server default level).
? Repeatable read.
? Serializable (the highest level, where transactions are completely isolated from one another).
Isolation level Dirty read Nonrepeatable read Phantom
Read uncommitted Yes Yes Yes
Read committed No Yes Yes
Repeatable read No No Yes
Serializable No No No
5. Uncommitted Dependency (Dirty Read) - Uncommitted dependency occurs when a second transaction selects a row that is being updated by another transaction. The second transaction is reading data that has not been committed yet and may be changed by the transaction updating the row. For example, an editor is making changes to an electronic document. During the changes, a second editor takes a copy of the document that includes all the changes made so far, and distributes the document to the intended audience.
Inconsistent Analysis (Nonrepeatable Read) Inconsistent analysis occurs when a second transaction accesses the same row several times and reads different data each time. Inconsistent analysis is similar to uncommitted dependency in that another transaction is changing the data that a second transaction is reading. However, in inconsistent analysis, the data read by the second transaction was committed by the transaction that made the change. Also, inconsistent analysis involves multiple reads (two or more) of the same row and each time the information is changed by another transaction; thus, the term nonrepeatable read. For example, an editor reads the same document twice, but between each reading, the writer rewrites the document. When the editor reads the document for the second time, it has changed.
Phantom Reads Phantom reads occur when an insert or delete action is performed against a row that belongs to a range of rows being read by a transaction. The transaction's first read of the range of rows shows a row that no longer exists in the second or succeeding read, as a result of a deletion by a different transaction. Similarly, as the result of an insert by a different transaction, the transaction's second or succeeding read shows a row that did not exist in the original read. For example, an editor makes changes to a document submitted by a writer, but when the changes are incorporated into the master copy of the document by the production department, they find that new unedited material has been added to the document by the author. This problem could be avoided if no one could add new material to the document until the editor and production department finish working with the original document.
6. nolock? What is the difference between the REPEATABLE READ and SERIALIZE isolation levels?
Locking Hints - A range of table-level locking hints can be specified using the SELECT, INSERT, UPDATE, and DELETE statements to direct Microsoft® SQL Server 2000 to the type of locks to be used. Table-level locking hints can be used when a finer control of the types of locks acquired on an object is required. These locking hints override the current transaction isolation level for the session.
Locking hint Description
HOLDLOCK Hold a shared lock until completion of the transaction instead of releasing the lock as soon as the required table, row, or data page is no longer required. HOLDLOCK is equivalent to SERIALIZABLE.
NOLOCK Do not issue shared locks and do not honor exclusive locks. When this option is in effect, it is possible to read an uncommitted transaction or a set of pages that are rolled back in the middle of a read. Dirty reads are possible. Only applies to the SELECT statement.
PAGLOCK Use page locks where a single table lock would usually be taken.
READCOMMITTED Perform a scan with the same locking semantics as a transaction running at the READ COMMITTED isolation level. By default, SQL Server 2000 operates at this isolation level.
READPAST Skip locked rows. This option causes a transaction to skip rows locked by other transactions that would ordinarily appear in the result set, rather than block the transaction waiting for the other transactions to release their locks on these rows. The READPAST lock hint applies only to transactions operating at READ COMMITTED isolation and will read only past row-level locks. Applies only to the SELECT statement.
READUNCOMMITTED Equivalent to NOLOCK.
REPEATABLEREAD Perform a scan with the same locking semantics as a transaction running at the REPEATABLE READ isolation level.
ROWLOCK Use row-level locks instead of the coarser-grained page- and table-level locks.
SERIALIZABLE Perform a scan with the same locking semantics as a transaction running at the SERIALIZABLE isolation level. Equivalent to HOLDLOCK.
TABLOCK Use a table lock instead of the finer-grained row- or page-level locks. SQL Server holds this lock until the end of the statement. However, if you also specify HOLDLOCK, the lock is held until the end of the transaction.
TABLOCKX Use an exclusive lock on a table. This lock prevents others from reading or updating the table and is held until the end of the statement or transaction.
UPDLOCK Use update locks instead of shared locks while reading a table, and hold locks until the end of the statement or transaction. UPDLOCK has the advantage of allowing you to read data (without blocking other readers) and update it later with the assurance that the data has not changed since you last read it.
XLOCK Use an exclusive lock that will be held until the end of the transaction on all data processed by the statement. This lock can be specified with either PAGLOCK or TABLOCK, in which case the exclusive lock applies to the appropriate level of granularity.
7. For example, if the transaction isolation level is set to SERIALIZABLE, and the table-level locking hint NOLOCK is used with the SELECT statement, key-range locks typically used to maintain serializable transactions are not taken.
USE pubs
GO
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
GO
BEGIN TRANSACTION
SELECT au_lname FROM authors WITH (NOLOCK)
GO
8. What is escalation of locks?
Lock escalation is the process of converting a lot of low level locks (like row locks, page locks) into higher level locks (like table locks). Every lock is a memory structure too many locks would mean, more memory being occupied by locks. To prevent this from happening, SQL Server escalates the many fine-grain locks to fewer coarse-grain locks. Lock escalation threshold was definable in SQL Server 6.5, but from SQL Server 7.0 onwards it's dynamically managed by SQL Server.
STORED PROCEDURES
1. What is Stored procedure?
A stored procedure is a set of Structured Query Language (SQL) statements that you assign a name to and store in a database in compiled form so that you can share it between a number of programs.
o They allow modular programming.
o They allow faster execution.
o They can reduce network traffic.
o They can be used as a security mechanism.
2. What are the different types of Storage Procedure?
a. Temporary Stored Procedures - SQL Server supports two types of temporary procedures: local and global. A local temporary procedure is visible only to the connection that created it. A global temporary procedure is available to all connections. Local temporary procedures are automatically dropped at the end of the current session. Global temporary procedures are dropped at the end of the last session using the procedure. Usually, this is when the session that created the procedure ends. Temporary procedures named with # and ## can be created by any user.
b. System stored procedures are created and stored in the master database and have the sp_ prefix.(or xp_) System stored procedures can be executed from any database without having to qualify the stored procedure name fully using the database name master. (If any user-created stored procedure has the same name as a system stored procedure, the user-created stored procedure will never be executed.)
c. Automatically Executing Stored Procedures - One or more stored procedures can execute automatically when SQL Server starts. The stored procedures must be created by the system administrator and executed under the sysadmin fixed server role as a background process. The procedure(s) cannot have any input parameters.
d. User stored procedure
3. How do I mark the stored procedure to automatic execution?
You can use the sp_procoption system stored procedure to mark the stored procedure to automatic execution when the SQL Server will start. Only objects in the master database owned by dbo can have the startup setting changed and this option is restricted to objects that have no parameters.
USE master
EXEC sp_procoption 'indRebuild', 'startup', 'true')
4. How can you optimize a stored procedure?
5. How will know whether the SQL statements are executed?
When used in a stored procedure, the RETURN statement can specify an integer value to return to the calling application, batch, or procedure. If no value is specified on RETURN, a stored procedure returns the value 0. The stored procedures return a value of 0 when no errors were encountered. Any nonzero value indicates an error occurred.
6. Why one should not prefix user stored procedures with sp_?
It is strongly recommended that you do not create any stored procedures using sp_ as a prefix. SQL Server always looks for a stored procedure beginning with sp_ in this order:
0. The stored procedure in the master database.
1. The stored procedure based on any qualifiers provided (database name or owner).
2. The stored procedure using dbo as the owner, if one is not specified.
Therefore, although the user-created stored procedure prefixed with sp_ may exist in the current database, the master database is always checked first, even if the stored procedure is qualified with the database name.
7. What can cause a Stored procedure execution plan to become invalidated and/or fall out of cache?
0. Server restart
1. Plan is aged out due to low use
2. DBCC FREEPROCCACHE (sometime desired to force it)
8. When do one need to recompile stored procedure?
if a new index is added from which the stored procedure might benefit, optimization does not automatically happen (until the next time the stored procedure is run after SQL Server is restarted).
9. SQL Server provides three ways to recompile a stored procedure:
? The sp_recompile system stored procedure forces a recompile of a stored procedure the next time it is run.
? Creating a stored procedure that specifies the WITH RECOMPILE option in its definition indicates that SQL Server does not cache a plan for this stored procedure; the stored procedure is recompiled each time it is executed. Use the WITH RECOMPILE option when stored procedures take parameters whose values differ widely between executions of the stored procedure, resulting in different execution plans to be created each time. Use of this option is uncommon, and causes the stored procedure to execute more slowly because the stored procedure must be recompiled each time it is executed.
? You can force the stored procedure to be recompiled by specifying the WITH RECOMPILE option when you execute the stored procedure. Use this option only if the parameter you are supplying is atypical or if the data has significantly changed since the stored procedure was created.
10. How to find out which stored procedure is recompiling? How to stop stored procedures from recompiling?
11. I have Two Stored Procedures SP1 and SP2 as given below. How the Transaction works, whether SP2 Transaction succeeds or fails?
CREATE PROCEDURE SP1 AS
BEGIN TRAN
INSERT INTO MARKS (SID,MARK,CID) VALUES (5,6,3)
EXEC SP2
ROLLBACK
GO
CREATE PROCEDURE SP2 AS
BEGIN TRAN
INSERT INTO MARKS (SID,MARK,CID) VALUES (100,100,103)
commit tran
GO
Both will get roll backed.
12. CREATE PROCEDURE SP1 AS
BEGIN TRAN
INSERT INTO MARKS (SID,MARK,CID) VALUES (5,6,3)
BEGIN TRAN
INSERT INTO STUDENT (SID,NAME1) VALUES (1,'SA')
commit tran
ROLLBACK TRAN
GO
Both will get roll backed.
13. How will you handle Errors in Sql Stored Procedure?
INSERT NonFatal VALUES (@Column2)
IF @@ERROR <>0
BEGIN
PRINT 'Error Occured'
END
http://www.sqlteam.com/item.asp?ItemID=2463
14. How will you raise an error in sql?
RAISERROR - Returns a user-defined error message and sets a system flag to record that an error has occurred. Using RAISERROR, the client can either retrieve an entry from the sysmessages table or build a message dynamically with user-specified severity and state information. After the message is defined it is sent back to the client as a server error message.
15. I have a stored procedure like
commit tran
create table a()
insert into table b
--
--
rollback tran
what will be the result? Is table created? data will be inserted in table b?
16. What do you do when one procedure is blocking the other?
**
17. How you will return XML from Stored Procedure?
You use the FOR XML clause of the SELECT statement, and within the FOR XML clause you specify an XML mode: RAW, AUTO, or EXPLICIT.
18. What are the differences between RAW, AUTO and Explicit modes in retrieving data from SQL Server in XML format?
**
19. Can a Stored Procedure call itself (recursive). If so then up to what level and can it be control?
Stored procedures are nested when one stored procedure calls another. You can nest stored procedures up to 32 levels. The nesting level increases by one when the called stored procedure begins execution and decreases by one when the called stored procedure completes execution. Attempting to exceed the maximum of 32 levels of nesting causes the whole calling stored procedure chain to fail. The current nesting level for the stored procedures in execution is stored in the @@NESTLEVEL function.
eg:
SET NOCOUNT ON
USE master
IF OBJECT_ID('dbo.sp_calcfactorial') IS NOT NULL
DROP PROC dbo.sp_calcfactorial
GO
CREATE PROC dbo.sp_calcfactorial
@base_number int, @factorial int OUT
AS
DECLARE @previous_number int
IF (@base_number<2) factorial="1" 1="1" previous_number="@base_number-1" factorial="-1)" factorial="@factorial*@base_number">(name varchar(10),salary getsal(name))
Here getsal is a user defined function which returns a salary type, when table is created no storage is allotted for salary type, and getsal function is also not executed, But when we are fetching some values from this table, getsal function get’s executed and the return
Type is returned as the result set.
25. How to debug a stored procedure?
TRIGGERS AND VIEWS
1. What is Trigger? What is its use? What are the types of Triggers? What are the new kinds of triggers in sql 2000?
Triggers are a special class of stored procedure defined to execute automatically when an UPDATE, INSERT, or DELETE statement is issued against a table or view. Triggers are powerful tools that sites can use to enforce their business rules automatically when data is modified.
The CREATE TRIGGER statement can be defined with the FOR UPDATE, FOR INSERT, or FOR DELETE clauses to target a trigger to a specific class of data modification actions. When FOR UPDATE is specified, the IF UPDATE (column_name) clause can be used to target a trigger to updates affecting a particular column.
You can use the FOR clause to specify when a trigger is executed:
? AFTER (default) - The trigger executes after the statement that triggered it completes. If the statement fails with an error, such as a constraint violation or syntax error, the trigger is not executed. AFTER triggers cannot be specified for views.
? INSTEAD OF -The trigger executes in place of the triggering action. INSTEAD OF triggers can be specified on both tables and views. You can define only one INSTEAD OF trigger for each triggering action (INSERT, UPDATE, and DELETE). INSTEAD OF triggers can be used to perform enhance integrity checks on the data values supplied in INSERT and UPDATE statements. INSTEAD OF triggers also let you specify actions that allow views, which would normally not support updates, to be updatable.
An INSTEAD OF trigger can take actions such as:
? Ignoring parts of a batch.
? Not processing a part of a batch and logging the problem rows.
? Taking an alternative action if an error condition is encountered.
In SQL Server 6.5 you could define only 3 triggers per table, one for INSERT, one for UPDATE and one for DELETE. From SQL Server 7.0 onwards, this restriction is gone, and you could create multiple triggers per each action. But in 7.0 there's no way to control the order in which the triggers fire. In SQL Server 2000 you could specify which trigger fires first or fires last using sp_settriggerorder.
Till SQL Server 7.0, triggers fire only after the data modification operation happens. So in a way, they are called post triggers. But in SQL Server 2000 you could create pre triggers also.
2. When should one use "instead of Trigger"? Example
CREATE TABLE BaseTable
(
PrimaryKey int IDENTITY(1,1),
Color nvarchar(10) NOT NULL,
Material nvarchar(10) NOT NULL,
ComputedCol AS (Color + Material)
)
GO
--Create a view that contains all columns from the base table.
CREATE VIEW InsteadView
AS SELECT PrimaryKey, Color, Material, ComputedCol
FROM BaseTable
GO
--Create an INSTEAD OF INSERT trigger on tthe view.
CREATE TRIGGER InsteadTrigger on InsteadView
INSTEAD OF INSERT
AS
BEGIN
--Build an INSERT statement ignoring inserrted.PrimaryKey and
--inserted.ComputedCol.
INSERT INTO BaseTable
SELECT Color, Material
FROM inserted
END
GO
-- can insert value to basetable by this insert into basetable(color,material) values ('red','abc')
-- insert into InsteadView(color,material)) values ('red','abc') can't do this.
-- It will give error "'PrimaryKey' iin table 'InsteadView' cannot be null."
-- can insert value through table by this< salary =" CASE" region =" ''WA''" city =" publishers.city)" city =" ANY" 1 =" In-process" 4 =" Local" 5 =" Both" hr =" sp_OACreate"> 0
BEGIN
EXEC sp_OAGetErrorInfo @object, @src OUT, @desc OUT
SELECT hr=convert(varbinary(4),@hr), Source=@src, Description=@desc
RETURN
END
B. Use CLSID - This example creates a SQL-DMO SQLServer object by using its CLSID.
DECLARE @object int
DECLARE @hr int
DECLARE @src varchar(255), @desc varchar(255)
EXEC @hr = sp_OACreate '{00026BA1-0000-0000-C000-000000000046}',
@object OUT
IF @hr <> 0
BEGIN
EXEC sp_OAGetErrorInfo @object, @src OUT, @desc OUT
SELECT hr=convert(varbinary(4),@hr), Source=@src, Description=@desc
RETURN
END
40. Difference between sysusers and syslogins?
sysusers - Contains one row for each Microsoft® Windows user, Windows group, Microsoft SQL Server™ user, or SQL Server role in the database.
syslogins - Contains one row for each login account.
41. What is the row size in SQL Server 2000?
8060 bytes.
42. How will you find structure of table, all tables/views in one db, all dbs?
//structure of table
sp_helpdb tbl_emp
//list of all databases
sp_helpdb
OR
SELECT * FROM master.dbo.sysdatabases
//details about database pubs. .mdf, .ldf file locations, size of database
sp_helpdb pubs
//lists all tables under current database
sp_tables
OR
SELECT * FROM information_schema.tables WHERE (table_type = 'base table')
OR
SELECT * FROM sysobjects WHERE type = 'U' //faster
43. B-tree indexes or doubly-linked lists?
44. What is the system function to get the current user's user id?
USER_ID(). Also check out other system functions like USER_NAME(), SYSTEM_USER, SESSION_USER, CURRENT_USER, USER, SUSER_SID(), HOST_NAME().
45. What are the series of steps that happen on execution of a query in a Query Analyzer?
1) Syntax checking 2) Parsing 3) Execution plan
46. Which event (Check constraints, Foreign Key, Rule, trigger, Primary key check) will be performed last for integrity check?
Identity Insert Check
Nullability constraint
Data type check
Instead of trigger
Primary key
Check constraint
Foreign key
DML Execution (update statements)
After Trigger
**
47. How will you show many to many relation in sql?
Create 3rd table with 2 columns which having one to many relation to these tables.
48. When a query is sent to the database and an index is not being used, what type of execution is taking place?
A table scan.
49. What is #, ##, @, @@ means?
@@ - System variables
@ - user defined variables
50. What is the difference between a Local temporary table and a Global temporary table? How is each one denoted?
Local temporary table will be accessible to only current user session, its name will be preceded with a single hash (#mytable)
Global temporary table will be accessible to all users, & it will be dropped only after ending of all active connections, its name will be preceded with double hash (##mytable)
51. What is covered queries in SQL Server?
52. What is HASH JOIN, MERGE JOIN?
TOOLS AND PERMISSIONS
1. Have you ever used DBCC command? Give an example for it.
The Transact-SQL programming language provides DBCC statements that act as Database Console Commands for Microsoft® SQL Serve 2000. These statements check the physical and logical consistency of a database. Many DBCC statements can fix detected problems. Database Console Command statements are grouped into these categories.
Statement category Perform
Maintenance statements Maintenance tasks on a database, index, or filegroup.
Miscellaneous statements Miscellaneous tasks such as enabling row-level locking or removing a dynamic-link library (DLL) from memory.
Status statements Status checks.
Validation statements Validation operations on a database, table, index, catalog, filegroup, system tables, or allocation of database pages.
DBCC CHECKDB, DBCC CHECKTABLE, DBCC CHECKCATALOG, DBCC CHECKALLOC, DBCC SHOWCONTIG, DBCC SHRINKDATABASE, DBCC SHRINKFILE etc.
2.
3. How do you use DBCC statements to monitor various aspects of a SQL server installation?
**
4. What is the output of DBCC Showcontig statement?
Displays fragmentation information for the data and indexes of the specified table.
5. How do I reset the identity column?
You can use the DBCC CHECKIDENT statement, if you want to reset or reseed the identity column. For example, if you need to force the current identity value in the jobs table to a value of 100, you can use the following:
USE pubs
GO
DBCC CHECKIDENT (jobs, RESEED, 100)
GO
6. About SQL Command line executables
Utilities
bcp
console
isql
sqlagent
sqldiag
sqlmaint
sqlservr
vswitch
dtsrun
dtswiz
isqlw
itwiz
odbccmpt
osql
rebuildm
sqlftwiz
distrib
logread
replmerg
snapshot
scm
regxmlss
7. What is DTC?
The Microsoft Distributed Transaction Coordinator (MS DTC) is a transaction manager that allows client applications to include several different sources of data in one transaction. MS DTC coordinates committing the distributed transaction across all the servers enlisted in the transaction.
8. What is DTS? Any drawbacks in using DTS?
Microsoft® SQL Server™ 2000 Data Transformation Services (DTS) is a set of graphical tools and programmable objects that lets you extract, transform, and consolidate data from disparate sources into single or multiple destinations.
9. What is BCP?
The bcp utility copies data between an instance of Microsoft® SQL Server™ 2000 and a data file in a user-specified format.
C:\Documents and Settings\sthomas>bcp
usage: bcp {dbtable | query} {in | out | queryout | format} datafile
[-m maxerrors] [-f formatfile] [-e errfile]
[-F firstrow] [-L lastrow] [-b batchsize]
[-n native type] [-c character type] [-w wide character type]
[-N keep non-text native] [-V file format version] [-q quoted identifier]
[-C code page specifier] [-t field terminator] [-r row terminator]
[-i inputfile] [-o outfile] [-a packetsize]
[-S server name] [-U username] [-P password]
[-T trusted connection] [-v version] [-R regional enable]
[-k keep null values] [-E keep identity values]
[-h "load hints"]
10. How can I create a plain-text flat file from SQL Server as input to another application?
One of the purposes of Extensible Markup Language (XML) is to solve challenges like this, but until all applications become XML-enabled, consider using our faithful standby, the bulk copy program (bcp) utility. This utility can do more than just dump a table; bcp also can take its input from a view instead of from a table. After you specify a view as the input source, you can limit the output to a subset of columns or to a subset of rows by selecting appropriate filtering (WHERE and HAVING) clauses.
More important, by using a view, you can export data from multiple joined tables. The only thing you cannot do is specify the sequence in which the rows are written to the flat file, because a view does not let you include an ORDER BY clause in it unless you also use the TOP keyword.
If you want to generate the data in a particular sequence or if you cannot predict the content of the data you want to export, be aware that in addition to a view, bcp also supports using an actual query. The only "gotcha" about using a query instead of a table or view is that you must specify queryout in place of out in the bcp command line.
For example, you can use bcp to generate from the pubs database a list of authors who reside in California by writing the following code:
bcp "SELECT * FROM pubs..authors WHERE state = 'CA'" queryout c:\CAauthors.txt -c -T -S
11. What are the different ways of moving data/databases between servers and databases in SQL Server?
There are lots of options available, you have to choose your option depending upon your requirements. Some of the options you have are: BACKUP/RESTORE, detaching and attaching databases, replication, DTS, BCP, logshipping, INSERT...SELECT, SELECT...INTO, creating INSERT scripts to generate data.
12. How will I export database?
Through DTS - Import/Export wizard
Backup - through Complete/Differential/Transaction Log
13. How to export database at a particular time, every week?
Backup - Schedule
DTS - Schedule
Jobs - create a new job
14. How do you load large data to the SQL server database?
bcp
15. How do you transfer data from text file to database (other than DTS)?
bcp
16. What is OSQL and ISQL utility?
The osql utility allows you to enter Transact-SQL statements, system procedures, and script files. This utility uses ODBC to communicate with the server.
The isql utility allows you to enter Transact-SQL statements, system procedures, and script files; and uses DB-Library to communicate with Microsoft® SQL Server™ 2000.
All DB-Library applications, such as isql, work as SQL Server 6.5–level clients when connected to SQL Server 2000. They do not support some SQL Server 2000 features.
The osql utility is based on ODBC and does support all SQL Server 2000 features. Use osql to run scripts that isql cannot run.
17. What Tool you have used for checking Query Optimization? What is the use of profiler in sql server? What is the first thing u look at in a SQL Profiler?
SQL Profiler is a graphical tool that allows system administrators to monitor events in an instance of Microsoft® SQL Server™. You can capture and save data about each event to a file or SQL Server table to analyze later. For example, you can monitor a production environment to see which stored procedures is hampering performance by executing too slowly.
Use SQL Profiler to:
? Monitor the performance of an instance of SQL Server.
? Debug Transact-SQL statements and stored procedures.
? Identify slow-executing queries.
? Test SQL statements and stored procedures in the development phase of a project by single-stepping through statements to confirm that the code works as expected.
? Troubleshoot problems in SQL Server by capturing events on a production system and replaying them on a test system. This is useful for testing or debugging purposes and allows users to continue using the production system without interference.
Audit and review activity that occurred on an instance of SQL Server. This allows a security administrator to review any of the auditing events, including the success and failure of a login attempt and the success and failure of permissions in accessing statements and objects.
Permissions
18. A user is a member of Public role and Sales role. Public role has the permission to select on all the table, and Sales role, which doesn’t have a select permission on some of the tables. Will that user be able to select from all tables?
**
19. If a user does not have permission on a table, but he has permission to a view created on it, will he be able to view the data in table?
Yes.
20. Describe Application Role and explain a scenario when you will use it?
**
21. After removing a table from database, what other related objects have to be dropped explicitly?
(view, SP)
22. You have a SP names YourSP and have the a Select Stmt inside the SP. You also have a user named YourUser. What permissions you will give him for accessing the SP.
**
23. Different Authentication modes in Sql server? If a user is logged under windows authentication mode, how to find his userid?
There are Three Different authentication modes in sqlserver.
1. Windows Authentication Mode
2. SqlServer Authentication Mode
3. Mixed Authentication Mode
“system_user” system function in sqlserver to fetch the logged on user name.
24. Give the connection strings from front-end for both type logins(windows,sqlserver)?
This are specifically for sqlserver not for any other RDBMS
Data Source=MySQLServer;Initial Catalog=NORTHWIND;Integrated Security=SSPI (windows)
Data Source=MySQLServer;Initial Catalog=NORTHWIND;Uid=” ”;Pwd=” ”(sqlserver)
25. What are three SQL keywords used to change or set someone’s permissions?
Grant, Deny and Revoke
ADMIN
1. Explain the architecture of SQL Server?
**
2. Different types of Backups?
o A full database backup is a full copy of the database.
o A transaction log backup copies only the transaction log.
o A differential backup copies only the database pages modified after the last full database backup.
o A file or filegroup restore allows the recovery of just the portion of a database that was on the failed disk.
3. What are ‘jobs’ in SQL Server? How do we create one? What is tasks?
Using SQL Server Agent jobs, you can automate administrative tasks and run them on a recurring basis.
**
4. What is database replication? What are the different types of replication you can set up in SQL Server? How are they used? What is snapshot replication how is it different from Transactional replication?
Replication is the process of copying/moving data between databases on the same or different servers. SQL Server supports the following types of replication scenarios:
1. Snapshot replication - It distributes data exactly as it appears at a specific moment in time and doesn’t monitor for updates. It can be used when data changes are infrequent. It is often used for browsing data such as price lists, online catalog, or data for decision support where the current data is not required and data is used as read only.
2. Transactional replication (with immediate updating subscribers, with queued updating subscribers) - With this an initial snapshot of data is applied, and whenever data modifications are made at the publisher, the individual transactions are captured and propagated to the subscribers.
3. Merge replication - It is the process of distributing the data between publisher and subscriber, it allows the publisher and subscriber to update the data while connected or disconnected, and then merging the updates between the sites when they are connected.
5. How can u look at what are the process running on SQL server? How can you kill a process in SQL server?
o Expand a server group, and then expand a server.
o Expand Management, and then expand Current Activity.
o Click Process Info. The current server activity is displayed in the details pane.
In the details pane, right-click a Process ID, and then click Kill Process.
6. What is RAID and what are different types of RAID configurations?
RAID stands for Redundant Array of Inexpensive Disks, used to provide fault tolerance to database servers. There are six RAID levels 0 through 5 offering different levels of performance, fault tolerance.
7.
Some of the tools/ways that help you troubleshooting performance problems are: SET SHOWPLAN_ALL ON, SET SHOWPLAN_TEXT ON, SET STATISTICS IO ON, SQL Server Profiler, Windows NT /2000 Performance monitor, Graphical execution plan in Query Analyzer.
8. How to determine the service pack currently installed on SQL Server?
The global variable @@Version stores the build number of the sqlservr.exe, which is used to determine the service pack installed.
eg: Microsoft SQL Server 2000 - 8.00.760 (Intel X86) Dec 17 2002 14:22:05 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.0 (Build 2195: Service Pack 3)
9. What is the purpose of using COLLATE in a query?
The term, collation, refers to a set of rules that determine how data is sorted and compared. In Microsoft® SQL Server 2000, it is not required to separately specify code page and sort order for character data, and the collation used for Unicode data. Instead, specify the collation name and sorting rules to use. Character data is sorted using rules that define the correct character sequence, with options for specifying case-sensitivity, accent marks, kana character types, and character width. Microsoft SQL Server 2000 collations include these groupings:
? Windows collations - Windows collations define rules for storing character data based on the rules defined for an associated Windows locale. The base Windows collation rules specify which alphabet or language is used when dictionary sorting is applied, as well as the code page used to store non-Unicode character data. For Windows collations, the nchar, nvarchar, and ntext data types have the same sorting behavior as char, varchar, and text data types
? SQL collations - SQL collations are provided for compatibility with sort orders in earlier versions of Microsoft SQL Server.
Sort Order
Binary is the fastest sorting order, and is case-sensitive. If Binary is selected, the Case-sensitive, Accent-sensitive, Kana-sensitive, and Width-sensitive options are not available.
Sort order Description
Binary Sorts and compares data in Microsoft® SQL Server™ tables based on the bit patterns defined for each character. Binary sort order is case-sensitive, that is lowercase precedes uppercase, and accent-sensitive. This is the fastest sorting order.
If this option is not selected, SQL Server follows sorting and comparison rules as defined in dictionaries for the associated language or alphabet.
Case-sensitive Specifies that SQL Server distinguish between uppercase and lowercase letters.
If not selected, SQL Server considers the uppercase and lowercase versions of letters to be equal. SQL Server does not define whether lowercase letters sort lower or higher in relation to uppercase letters when Case-sensitive is not selected.
Accent-sensitive Specifies that SQL Server distinguish between accented and unaccented characters. For example, 'a' is not equal to 'รก'.
If not selected, SQL Server considers the accented and unaccented versions of letters to be equal.
Kana-sensitive Specifies that SQL Server distinguish between the two types of Japanese kana characters: Hiragana and Katakana.
If not selected, SQL Server considers Hiragana and Katakana characters to be equal.
Width-sensitive Specifies that SQL Server distinguish between a single-byte character (half-width) and the same character when represented as a double-byte character (full-width).
If not selected, SQL Server considers the single-byte and double-byte representation of the same character to be equal.
Windows collation options:
? Use Latin1_General for the U.S. English character set (code page 1252).
? Use Modern_Spanish for all variations of Spanish, which also use the same character set as U.S. English (code page 1252).
? Use Arabic for all variations of Arabic, which use the Arabic character set (code page 1256).
? Use Japanese_Unicode for the Unicode version of Japanese (code page 932), which has a different sort order from Japanese, but the same code page (932).
10. What is the STUFF Function and how does it differ from the REPLACE function?
STUFF - Deletes a specified length of characters and inserts another set of characters at a specified starting point.
SELECT STUFF('abcdef', 2, 3, 'ijklmn')
GO
Here is the result set:
---------
aijklmnef
REPLACE - Replaces all occurrences of the second given string expression in the first string expression with a third expression.
SELECT REPLACE('abcdefghicde','cde','xxx')
GO
Here is the result set:
------------
abxxxfghixxx
11. What does it mean to have quoted_identifier on? What are the implications of having it off?
When SET QUOTED_IDENTIFIER is OFF (default), literal strings in expressions can be delimited by single or double quotation marks.
When SET QUOTED_IDENTIFIER is ON, all strings delimited by double quotation marks are interpreted as object identifiers. Therefore, quoted identifiers do not have to follow the Transact-SQL rules for identifiers.
SET QUOTED_IDENTIFIER must be ON when creating or manipulating indexes on computed columns or indexed views. If SET QUOTED_IDENTIFIER is OFF, CREATE, UPDATE, INSERT, and DELETE statements on tables with indexes on computed columns or indexed views will fail.
The SQL Server ODBC driver and Microsoft OLE DB Provider for SQL Server automatically set QUOTED_IDENTIFIER to ON when connecting.
When a stored procedure is created, the SET QUOTED_IDENTIFIER and SET ANSI_NULLS settings are captured and used for subsequent invocations of that stored procedure. When executed inside a stored procedure, the setting of SET QUOTED_IDENTIFIER is not changed.
SET QUOTED_IDENTIFIER OFF
GO
-- Attempt to create a table with a reserved keyword as a name
-- should fail.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
SET QUOTED_IDENTIFIER ON
GO
-- Will succeed.
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
GO
12. What is the purpose of UPDATE STATISTICS?
Updates information about the distribution of key values for one or more statistics groups (collections) in the specified table or indexed view.
13. Fundamentals of Data warehousing & olap?
14. What do u mean by OLAP server? What is the difference between OLAP and OLTP?
15. What is a tuple?
A tuple is an instance of data within a relational database.
16. Services and user Accounts maintenance
17. sp_configure commands?
Displays or changes global configuration settings for the current server.
18. What is the basic functions for master, msdb, tempdb databases?
Microsoft® SQL Server 2000 systems have four system databases:
? master - The master database records all of the system level information for a SQL Server system. It records all login accounts and all system configuration settings. master is the database that records the existence of all other databases, including the location of the database files.
? tempdb - tempdb holds all temporary tables and temporary stored procedures. It also fills any other temporary storage needs such as work tables generated by SQL Server. tempdb is re-created every time SQL Server is started so the system starts with a clean copy of the database.
By default, tempdb autogrows as needed while SQL Server is running. If the size defined for tempdb is small, part of your system processing load may be taken up with autogrowing tempdb to the size needed to support your workload each time to restart SQL Server. You can avoid this overhead by using ALTER DATABASE to increase the size of tempdb.
? model - The model database is used as the template for all databases created on a system. When a CREATE DATABASE statement is issued, the first part of the database is created by copying in the contents of the model database, then the remainder of the new database is filled with empty pages. Because tempdb is created every time SQL Server is started, the model database must always exist on a SQL Server system.
? msdb - The msdb database is used by SQL Server Agent for scheduling alerts and jobs, and recording operators.
19. What are sequence diagrams? What you will get out of this sequence diagrams?
Sequence diagrams document the interactions between classes to achieve a result, such as a use case. Because UML is designed for object-oriented programming, these communications between classes are known as messages. The sequence diagram lists objects horizontally, and time vertically, and models these messages over time.
20. What are the new features of SQL 2000 than SQL 7? What are the new datatypes in sql?
? XML Support - The relational database engine can return data as Extensible Markup Language (XML) documents. Additionally, XML can also be used to insert, update, and delete values in the database. (for xml raw - to retrieve output as xml type)
? User-Defined Functions - The programmability of Transact-SQL can be extended by creating your own Transact-SQL functions. A user-defined function can return either a scalar value or a table.
? Indexed Views - Indexed views can significantly improve the performance of an application where queries frequently perform certain joins or aggregations. An indexed view allows indexes to be created on views, where the result set of the view is stored and indexed in the database.
? New Data Types - SQL Server 2000 introduces three new data types. bigint is an 8-byte integer type. sql_variant is a type that allows the storage of data values of different data types. table is a type that allows applications to store results temporarily for later use. It is supported for variables, and as the return type for user-defined functions.
? INSTEAD OF and AFTER Triggers - INSTEAD OF triggers are executed instead of the triggering action (for example, INSERT, UPDATE, DELETE). They can also be defined on views, in which case they greatly extend the types of updates a view can support. AFTER triggers fire after the triggering action. SQL Server 2000 introduces the ability to specify which AFTER triggers fire first and last.
? Multiple Instances of SQL Server - SQL Server 2000 supports running multiple instances of the relational database engine on the same computer. Each computer can run one instance of the relational database engine from SQL Server version 6.5 or 7.0, along with one or more instances of the database engine from SQL Server 2000. Each instance has its own set of system and user databases.
? Index Enhancements - You can now create indexes on computed columns. You can specify whether indexes are built in ascending or descending order, and if the database engine should use parallel scanning and sorting during index creation.
21. How do we open SQL Server in single user mode?
We can accomplish this in any of the three ways given below :-
. From Command Prompt :-
sqlservr -m
a. From Startup Options :-
Go to SQL Server Properties by right-clicking on the Server name in the Enterprise manager.
Under the 'General' tab, click on 'Startup Parameters'.
Enter a value of -m in the Parameter.
b. From Registry :-
Go to HKEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServer\MSSQLServer\Parameters.
Add new string value.
Specify the 'Name' as SQLArg(n) & 'Data' as -m.
Where n is the argument number in the list of arguments.
24. What is Log Shipping?
In Microsoft® SQL Server™ 2000 Enterprise Edition, you can use log shipping to feed transaction logs from one database to another on a constant basis. Continually backing up the transaction logs from a source database and then copying and restoring the logs to a destination database keeps the destination database synchronized with the source database. This allows you to have a backup server and also provides a way to offload query processing from the main computer (the source server) to read-only destination servers.
25. What are the main steps you take care for enhancing SQL Server performance?
**
26. You have to check whether any users are connected to sql server database and if any user is connected to database, you have to disconnect the user(s) and run a process in a job. How do you do the above in a job?
**
XML
27. How can I convert data in a Microsoft Access table into XML format?
The following applications can help you convert Access data into XML format: Access 2002, ADO 2.5, and SQLXML. Access 2002 (part of Microsoft Office XP) enables you to query or save a table in XML format. You might be able to automate this process. ADO 2.5 and later enables you to open the data into a recordset, then persist the recordset in XML format, as the following code shows:
rs.Save "c:\rs.xml", adPersistXML
You can use linked servers to add the Access database to your SQL Server 2000 database so you can run queries from within SQL Server to retrieve data. Then, through HTTP, you can use the SQLXML technology to extract the Access data in the XML format you want.
NEW
28. @@IDENTITY ?
Ans: Returns the last-inserted identity value.
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