如何更改约束 [英] How to Alter Constraint

问题描述

SQL如何更改约束

以下是我的约束条件之一

Below is 1 of my constraint

CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode),

我要添加

ON DELETE CASCADE

以上约束.

如何更改现有约束ACTIVEPROG_FKEY1并添加

How do i alter that existing constraint ACTIVEPROG_FKEY1 and add

ON DELETE CASCADE

约束ACTIVEPROG_FKEY1

to constraint ACTIVEPROG_FKEY1

考虑"ACTIVEPROG_FKEY1"在表"ACTIVEPROG"中

Consider ACTIVEPROG_FKEY1 is at Table ACTIVEPROG

推荐答案

您永远无法更改约束，但可以删除约束然后重新创建.

You can not alter constraints ever but you can drop them and then recreate.

看看这个

ALTER TABLE your_table DROP CONSTRAINT ACTIVEPROG_FKEY1;

，然后像这样用ON DELETE CASCADE重新创建

and then recreate it with ON DELETE CASCADE like this

ALTER TABLE your_table
add CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode)
    ON DELETE CASCADE;

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