Globally Unique Identifiers, or GUIDs, are 16-byte (128-bit) binary data types in SQLServer that contain values and are represented by unique identifiers. Each table modeling procedure starts with a business key, surrogate key, identity key, etc.
The objective of this tip is to present and describe several T-SQL examples for creating, using, and analyzing GUIDs. This tip includes a T-SQL code sample for empirically analyzing the uniqueness of GUID values.
GUID is a 16 byte binary SQLServer data type that is globally unique across tables, databases, and servers. The term GUID stands for Globally Unique Identifier and it is used interchangeably with UNIQUEIDENTIFIER.
If you plan to use GUID, use uniqueidentifier instead of varchar as data type. Microsoft did not mention how they implement it, there is some speed optimization when you use uniqueidentifier as the data type.
All column constraints and properties, except IDENTITY, can be used on the uniqueidentifier data type. Merge replication and transactional replication with updating subscriptions use uniqueidentifier columns to guarantee that rows are uniquely identified across multiple copies of the table.
A Universally Unique Identifier (UUID), also known as a GUID (Globally Unique Identifier) in Microsoft technologies, is a 128-bit value used to uniquely identify records in databases.
A GUID is guaranteed to be unique across tables, databases, and even servers. In SQLServer, GUID is 16-byte binary data type, which is generated by using the NEWID() function:
This guide will walk you through using the UNIQUEIDENTIFIER data type (SQLServer’s implementation of GUID) as the primary key for an Employee table in SQLServer 2008. We’ll cover everything from table creation to best practices, with clear examples for beginners and experts alike.
In this comprehensive guide, we‘ll unpack everything related to storing and working with GUIDs built right into SQLServer‘s database engine. We have a lot to cover, so buckle up for code examples, performance benchmarks, and helpful explanations along the way!
There are many SQLServer databases designed to use GUID as a surrogate, primary key, and/or clustered index key. This is to enforce entity (table) integrity and/or logical order of the rows.
A GUID is guaranteed to be unique across tables, databases, and even servers. In SQL Server, GUID is 16-byte binary data type, which is generated by using the NEWID() function: