GUID stands for “Global Unique Identifier” and is a term usually referring to Microsoft’s implementation of unique identity number (in a distributed environment) that it generates to identify different entities such documents, COM’s, DLL’s, interfaces, records, and other objects. It is also known as UUID – Universal Unique Identifier interchangeably.
GUID implemenation is a 128 bit (16 byte) value consisting of sets of hexadecimal digits separated by hyphens. As the total number of unique keys is large the probability of two numbers being the same is very small.
The AutoNumber datatype in MS-Access and the Identity datatype in SQL Server is a GUID implementation.
(more…)
