System Datatype Vs User Defined Datatype

System Datatype		User Defined Datatype
1	System Data type is defined by the System.	User Defined Data type defined by the User.
2	There are more than 25 System Data type available in SQL Server.	User Defined Data type is also System data type, just name of that Data type is Changed by the User.
3	Example : Col1 BIGINT In this Example BIGINT is a System Data type	Example : SP_ADDTYPE ‘pk’, BIGINT In this Example ‘PK’ is User Defined Data type. You can use PK Anywhere instead of BIGINT.