A user-defined distinct type (UDT) is a data type based on a system supplied data type that the user creates in order to meet specific business needs. This new type behaves independently on the system and can be defined for a variety of behaviors. You cannot create a user-defined type based on another user-defined type. Also, UDTs are created with strong typing. This means that only functions and operators defined on the UDT can be applied to its instances.
For a listing of built-in data types, see Data Types.
Here are some tasks that you can perform on distinct types:
For more information about distinct types, see User-defined distinct types (UDT) in the SQL Programming
topic in the Information Center .