Drops a cast definition for a UDT from the data dictionary.
You can also drop the system-generated casts for distinct UDTs. The system does not drop the associated external cast routine when you perform DROP CAST.
You should not drop a cast if it is referenced by a view, stored procedure, trigger, or macro. There are no restrictions on dropping a cast. The system always honors a DROP CAST request whether it is referenced by a view, stored procedure, trigger, or macro. However, after you drop a cast, any attempt to use a view, stored procedure, trigger, or macro that references the dropped cast returns an error to the requestor.
You must have either the UDTTYPE or the UDTMETHOD privilege on the SYSUDTLIB database to drop a user-defined cast for a UDT.