Remove all mandatory foreign key constraints in Oracle

--Query the foreign key for all tables of the user, owner condition is user
SELECT * from user_constraints c where c.constraint_type = ' R ' and C.owner = ' A ';

--delete foreign keys for all tables of the user, owner condition is user

Select ' ALTER TABLE ' | | t.table_name| | ' drop constraint ' | | t.constraint_name| | '; ' from User_constraints t
where t.constraint_type= ' R ' and C.owner = ' A ';

Remove all mandatory foreign key constraints in Oracle