1.enable constraints
select 'alter table '||table_name ||' ENABLE CONSTRAINT '|| CONSTRAINT_name ||';' from user_constraints;
select 'alter table '||table_name ||' ENABLE CONSTRAINT '|| CONSTRAINT_name ||';' from user_constraints;
2.DISABLE constraints
select 'alter table '||table_name ||' DISABLE CONSTRAINT '|| CONSTRAINT_name ||';' from user_constraints ;