When you select a distinct type from the contents pane and select Show Related for that object, the Show Related dialog lists any objects with first-level dependencies on that distinct type. The related object can be schema. You can view second-level dependencies by selecting Show Related for each object with a first-level dependency.
Distinct types or user-defined data types are created at the subsystem level. If tables have been defined using a distinct type, you will not be allowed to drop the distinct type without first dropping the table.
A distinct type can not dropped if any of the following dependencies exist:
Whenever a distinct type is dropped, all privileges on the distinct type are also dropped. In addition, the cast functions that were generated when the distinct type was created and the privileges on those cast functions are also dropped.
When you drop a distinct type, the schema with which it is associated remains unchanged.