ORA-01922: CASCADE must be specified to drop 'username'

Hi, this is a common issue when you try to delete OBIEE11G Schema (DEV_BIPLATFORM and DEV_MDS) from Database. The best way to avoid it is by using RCU itself. But if you want to delete it manually, read further.

This error is issued if someone tries to drop a user when the user to be dropped still has objects. In order to drop the user and all his objects, use key word cascade.
Like,

drop user DEV_MDS cascade;

drop user DEV_BIPLATFORM cascade;

Make sure that you have Admin privileges. Or connect as sys user and delete the user.