There must be an existing transform group definition to be able to drop that definition. If there is no existing transform group defined for the specified UDT, the request aborts and the system returns an error to the requestor.
The system always honors a DROP TRANSFORM request whether it is referenced by a view, stored procedure, trigger, or macro.
However, for a transform to be dropped, the UDT on which it is defined must not be used by any table in the system. There is no restriction on replacing a transform definition, however, so if you only need to replace, but not drop, a transform definition to correct or revise its definition, you should use the REPLACE TRANSFORM statement instead. See CREATE TRANSFORM and REPLACE TRANSFORM.
The drop transform operation succeeds even if the ordering is referenced by a view, stored procedure, trigger, or macro. However, if you attempt to use a view, stored procedure, trigger or macro that references a dropped ordering operation, the request returns an error to the requestor.