About constraint's disable and enable

Establish the constraint of the primary foreign key

CREATE TABLE EMP1 (emp_no number (2) Constraint EMP_EMP_NO_PK primary key,
ename VARCHAR2 (15),
Salary number (8,2),
Mgr_no number (2) constraint EMP_MGR_FK references emp1);

Query status

Sql> Select Constraint_name,constraint_type, status from User_constraints where Table_name= ' EMP1 '
2;

Constraint_name C STATUS
------------------------------ - --------
EMP_EMP_NO_PK P ENABLED
EMP_MGR_FK R ENABLED

ALTER TABLE EMP1 disable constraint EMP_EMP_NO_PK cascade;

Sql> Select Constraint_name,constraint_type, status from User_constraints where table_name= ' EMP1 ';

Constraint_name C STATUS
------------------------------ - --------
EMP_EMP_NO_PK P DISABLED
EMP_MGR_FK R DISABLED

ALTER TABLE EMP1 enable constraint emp_emp_no_pk;

Sql> Select Constraint_name,constraint_type, status from User_constraints where table_name= ' EMP1 ';

Constraint_name C STATUS
------------------------------ - --------
EMP_EMP_NO_PK P ENABLED
EMP_MGR_FK R DISABLED

Still need manual enable foreign KEY constraint

ALTER TABLE EMP1 enable constraint EMP_MGR_FK;

Sql> Select Constraint_name,constraint_type, status from User_constraints where Table_name= ' EMP1 '
2;

Constraint_name C STATUS
------------------------------ - --------
EMP_EMP_NO_PK P ENABLED
EMP_MGR_FK R ENABLED

About constraint's disable and enable