--disable fk

SELECT 'ALTER TABLE '|| table_name || ' DISABLE CONSTRAINTS ' || t.constraint_name ||';'

FROM user_constraints t

WHERE t.constraint_type = 'R';

--enable fk

SELECT 'ALTER TABLE '|| table_name || ' ENABLE CONSTRAINTS ' || t.constraint_name ||';'

FROM user_constraints t

WHERE t.constraint_type = 'R';