User Defined Data Types in Microsoft SQL Server

User defined data types in Microsoft SQL Server are based on system data types.

User defined data types are used when multiple tables need to store the same type of data in a column and you need to ensure that all these columns are exactly the same including length, and nullability.

User defined datatype contains following parameters:

• Name
• System data type on which user defined data type is based upon.
• Nullability

For example

User defined data type in Microsoft SQL Server called user_string could be created based on char system data type.

See Also