select CONSTRAINT_NAME from user_constraints where table_name='TBL_EMPLOYEE';
select CONSTRAINT_NAME,COLUMN_NAME from user_cons_columns where table_name='TBL_EMPLOYEE';
select CONSTRAINT_NAME from user_constraints where table_name='TBL_EMPLOYEE';
select CONSTRAINT_NAME,COLUMN_NAME from user_cons_columns where table_name='TBL_EMPLOYEE';