User-defined data types are like user-defined functions to create customized data types.
UDD Type Example
For example, CREATE DISTINCT TYPE AUDIO AS BLOB(1M);
So now the “audio” becomes a new data-type. If we talk about user defined data types, there are 2 types.
In this case, the only user-defined type is customized based on an existing type
CREATE TYPE PERSON_DET AS (NAME CHAR(20),
REF USING VARCAHR(13) FOR BIT DATA
MODE DB2 SQL;
The basic difference is , we can create a structure with mix of db2 existing types and UDTs.
The usage for UDTs we can see in the Banking domain.