A View with a CHECK OPTION Constraint
You can specify that DML statements on a view must satisfy the subquery using a CHECK OPTION
constraint.
CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
ENAME VARCHAR2(10),
JOB VARCHAR2(9),
SAL NUMBER(7, 2),
DEPTNO NUMBER(2));
INSERT INTO EMP VALUES (1, 'SMITH', 'CLERK', 800, 20);
INSERT INTO EMP VALUES (2, 'ALLEN', 'SALESMAN', 1600, 30);
INSERT INTO EMP VALUES (3, 'WARD', 'SALESMAN', 1250, 30);
INSERT INTO EMP VALUES (4, 'JONES', 'MANAGER', 2975, 20);
INSERT INTO EMP VALUES (5, 'MARTIN','SALESMAN', 1250, 30);
INSERT INTO EMP VALUES (6, 'BLAKE', 'MANAGER', 2850, 30);
INSERT INTO EMP VALUES (7, 'CLARK', 'MANAGER', 2850, 10);
INSERT INTO EMP VALUES (8, 'SCOTT', 'ANALYST', 3000, 20);
INSERT INTO EMP VALUES (9, 'KING', 'PRESIDENT',3000, 10);
INSERT INTO EMP VALUES (10,'TURNER','SALESMAN', 1500, 30);
INSERT INTO EMP VALUES (11,'ADAMS', 'CLERK', 1500, 20);
SQL> CREATE VIEW emp_view AS
2 SELECT *
3 FROM emp
4 WHERE sal < 1500
5 WITH CHECK OPTION CONSTRAINT view_salary;
View created.
SQL>
The database would return an error because the row isn't retrievable by the view:
INSERT INTO emp_view (empno, sal) VALUES (1, 19000);
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Views:
- Creating and Using a View
- Creating and Using Simple Views
- Performing an INSERT Using a View
- A View with a CHECK OPTION Constraint
- View with a READ ONLY Constraint
- Getting Information on View Definitions with DESCRIBE command
- Getting Information on View Definitions with user_views view
- Retrieving Information on View Constraints
- Creating and Using Complex Views
- Modifying a View
- Alter the constraints on a view using ALTER VIEW
- Dropping a View
Related: