if oracle db refuse to drop a constraint with message “Remove all references to the key before the key is to be dropped”. It’s clear that we must drop references before. But how to list these references.

Sql command bellow help to list all constraints which uses the constraint to be dropped “CONSTRAINT_TO_BE_DROPPED_NAME”

select * from all_constraints
where constraint_type='R' and 
r_constraint_name='CONSTRAINT_TO_BE_DROPPED_NAME';