What is GUID , why we use it? [Resolved]

1. GUID is Short form of Globally Unique Identifier, a unique 128-bit number that is produced by the Windows OS or by some Windows applications to identify a particular component, application, file, database entry, and/or user.
2. For instance, a Web site may generate a GUID and assign it to a user's browser to record and track the session.
3. A GUID is also used in a Windows registry to identify COM DLLs.
4. Knowing where to look in the registry and having the correct GUID yields a lot information about a COM object (i.e., information in the type library, its physical location, etc.).
5. Windows also identifies user accounts by a username (computer/domain and username) and assigns it a GUID.
6. Some database administrators even will use GUIDs as primary key values in databases.
7. GUIDs can be created in a number of ways, but usually they are a combination of a few unique settings based on specific point in time (e.g., an
IP address, network MAC address, clock date/time, etc.).

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GUID is just like a Random combination of string and number,because it's generating new string every time when assigned to a variable.

It's full form is Globally Unique Identifier.

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Also go through below links:-

http://www.webopedia.com/TERM/G/GUID.html
http://en.wikipedia.org/wiki/Globally_unique_identifier
http://msdn.microsoft.com/en-us/library/system.guid.newguid%28v=vs.110%29.aspx
http://forums.asp.net/t/1127782.aspx

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