A UDT can only exist on the database. Each UDT has an associated “from-sql routine” and “to-sql routine”.
- Insert – The “to-sql routine” constructs a UDT value from a pre-defined type value. The “to-sql routine” is automatically invoked when inserting values from a client system into a UDT on the database.
- Retrieve – The “from-sql routine” generates a pre-defined type value from a UDT. The “from-sql routine” is automatically invoked when a UDT is retrieved from the database to a client system.