Guid in SQL Server

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In this video we will discuss
1. What is a GUID in SQL Server
2. When to use GUID
3. Advantages and disadvantages of using a GUID

What is GUID data type in SQL Server
The GUID data type is a 16 byte binary data type that is globally unique. GUID stands for Global Unique Identifier. The terms GUID and UNIQUEIDENTIFIER are used interchangeably.

To declare a GUID variable, we use the keyword UNIQUEIDENTIFIER

Declare @ID UNIQUEIDENTIFIER
SELECT @ID = NEWID()
SELECT @ID as MYGUID

How to create GUID in sql server
To create a GUID in SQL Server use NEWID() function

For example, SELECT NEWID(), creates a GUID that is guaranteed to be unique across tables, databases, and servers. Every time you execute SELECT NEWID() query, you get a GUID that is unique.

Example GUID : 0BB83607-00D7-4B2C-8695-32AD3812B6F4

When to use GUID data type : Let us understand when to use a GUID in SQL Server with an example.

For example code used in the demo please refer to the following article
http://csharp-video-tutorials.blogspot.com/2017/03/guid-in-sql-server.html

The main advantage of using a GUID is that it is unique across tables, databases and servers. It is extremely useful if you’re consolidating records from multiple SQL Servers into a single table.

The main disadvantage of using a GUID as a key is that it is 16 bytes in size. It is one of the largest datatypes in SQL Server. An integer on the other hand is 4 bytes,

An Index built on a GUID is larger and slower than an index built on integer column. In addition a GUID is hard to read compared to int.

So in summary, use a GUID when you really need a globally unique identifier. In all other cases it is better to use an INT data type.