Drop cascade constraints Demo
SQL> CREATE TABLE Employee(Employee_ID NUMBER(4) NOT NULL,
2 Employee_Name VARCHAR2(10),
3 JOB VARCHAR2(9),
4 Manager_ID NUMBER(4),
5 Start_Date DATE,
6 Salary NUMBER(7, 2),
7 COMM NUMBER(7, 2),
8 Deparment_ID NUMBER(2)
9 );
Table created.
SQL>
SQL> INSERT INTO Employee VALUES (7369, 'SMITH', 'CLERK', 7902, TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20);
1 row created.
SQL> INSERT INTO Employee VALUES (7499, 'ALLEN', 'SALESMAN', 7698, TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7521, 'WARD', 'SALESMAN', 7698, TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7566, 'JONES', 'MANAGER', 7839, TO_DATE('2-APR-1981', 'DD-MON-YYYY'), 2975, NULL, 20);
1 row created.
SQL> INSERT INTO Employee VALUES (7654, 'MARTIN', 'SALESMAN', 7698, TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7698, 'BLAKE', 'MANAGER', 7839, TO_DATE('1-MAY-1981', 'DD-MON-YYYY'), 2850, NULL, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7782, 'CLARK', 'MANAGER', 7839, TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10);
1 row created.
SQL> INSERT INTO Employee VALUES (7788, 'SCOTT', 'ANALYST', 7566, TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO Employee VALUES (7839, 'KING', 'PRESIDENT', NULL, TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);
1 row created.
SQL> INSERT INTO Employee VALUES (7844, 'TURNER', 'SALESMAN', 7698, TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7876, 'ADAMS', 'CLERK', 7788, TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);
1 row created.
SQL> INSERT INTO Employee VALUES (7900, 'JAMES', 'CLERK', 7698, TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 950, NULL, 30);
1 row created.
SQL> INSERT INTO Employee VALUES (7902, 'FORD', 'ANALYST', 7566, TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO Employee VALUES (7934, 'MILLER', 'CLERK', 7782, TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);
1 row created.
SQL>
SQL> CREATE TABLE Department(Deparment_ID NUMBER(2),
2 Department_Name VARCHAR2(14),
3 Location VARCHAR2(13)
4 );
Table created.
SQL>
SQL> INSERT INTO Department VALUES (10, 'ACCOUNTING', 'NEW YORK');
1 row created.
SQL> INSERT INTO Department VALUES (20, 'RESEARCH', 'DALLAS');
1 row created.
SQL> INSERT INTO Department VALUES (30, 'SALES', 'CHICAGO');
1 row created.
SQL> INSERT INTO Department VALUES (40, 'OPERATIONS', 'BOSTON');
1 row created.
SQL>
SQL> alter table Employee add constraint Employee_pk primary key(Employee_ID);
Table altered.
SQL> alter table Department add constraint Department_pk primary key(Deparment_ID);
Table altered.
SQL> alter table Employee add constraint Employee_fk_Department foreign key(Deparment_ID) references Department;
Table altered.
SQL> alter table Employee add constraint Employee_fk_Employee foreign key(Manager_ID) references Employee;
Table altered.
SQL>
SQL> select * from Employee;
EMPLOYEE_ID EMPLOYEE_N JOB MANAGER_ID START_DAT SALARY COMM DEPARMENT_ID
----------- ---------- --------- ---------- --------- ---------- ---------- ------------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 09-DEC-82 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 12-JAN-83 1100 20
EMPLOYEE_ID EMPLOYEE_N JOB MANAGER_ID START_DAT SALARY COMM DEPARMENT_ID
----------- ---------- --------- ---------- --------- ---------- ---------- ------------
7900 JAMES CLERK 7698 03-DEC-81 950 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
SQL> select * from Department;
DEPARMENT_ID DEPARTMENT_NAM LOCATION
------------ -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SQL>
SQL> drop table Department cascade constraints;
Table dropped.
SQL> drop table Employee cascade constraints;
Table dropped.
SQL>
SQL>
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