User-defined types
A user-defined type (UDT) is a data type that you derive from existing data types, but is nevertheless considered to be separate and incompatible from them. UDTs enable you to extend the built-in types already available in Db2® and create your own customized data types.
The SYSCAT.DATATYPES catalog view allows you to see the UDTs that are defined for your database. This catalog view also shows you the data types defined by the database manager when the database was created.
A UDT cannot be used as an argument for most of the system-provided, or built-in, functions. User-defined functions must be provided to enable these and other operations.