1. What Are The Advantages Of Using With Check Option When Defining The Views
2. Update With Check Option Oracle Card

20.5.4 The View WITH CHECK OPTION ClauseThe WITH CHECK OPTION clause can be given foran updatable view to prevent inserts to rows for which theWHERE clause in theselectstatement is not true. It alsoprevents updates to rows for which the WHEREclause is true but the update would cause it to be not true (inother words, it prevents visible rows from being updated tononvisible rows).In a WITH CHECK OPTION clause for an updatableview, the LOCAL and CASCADEDkeywords determine the scope of check testing when the view isdefined in terms of another view. When neither keyword is given,the default is CASCADED. TheLOCAL keyword restricts the CHECKOPTION only to the view being defined.CASCADED causes the checks for underlying viewsto be evaluated as well.Consider the definitions for the following table and set of views:CREATE TABLE t1 (a INT);CREATE VIEW v1 AS SELECT. FROM t1 WHERE a 0WITH LOCAL CHECK OPTION;CREATE VIEW v3 AS SELECT. FROM v1 WHERE a 0WITH CASCADED CHECK OPTION;Here the v2 and v3 views aredefined in terms of another view, v1.v2 has a LOCAL check option,so inserts are tested only against the v2check. V3 has a CASCADEDcheck option, so inserts are tested not only against its owncheck, but against those of underlying views.

What Are The Advantages Of Using With Check Option When Defining The Views

Update With Check Option Oracle Card

The followingstatements illustrate these differences:mysql INSERT INTO v2 VALUES (2);Query OK, 1 row affected (0.00 sec)mysql INSERT INTO v3 VALUES (2);ERROR 1369 (HY000): CHECK OPTION failed 'test.v3'.