1?組合特性說明

?	Validate		Novalidate
	已有記錄	新增/刪除記錄	已有記錄	新增/刪除記錄
Enable	Yes	Yes	No	Yes
Disable	Yes	No	No	No

Validate確保已有數據符合約束；

Novalidate不必考慮已有數據是否符合約束。

?

除非Novalidate被指定，Enable默認Validate；

除非Validate被指定，Disable默認Novalidate。

?

Enable Validate與Enable相同，檢查已有記錄和新增記錄，確保都符合約束；

Enable Novalidate?允許已有記錄不必滿足約束條件，但新增/修改的記錄必須滿足；

Disable Validate禁用約束，刪除約束上的索引，不允許修改任何被約束的記錄；

Disable Novalidate與Disable相同，禁用約束，刪除約束上的索引，且允許修改被約束的記錄。

2?建表

SQL> create table test(id int, name varchar2(10));

Table created

SQL> alter table test add constraint ck_id check(id > 10);

Table altered

3?測試1: Enable Validate

SQL> alter table test Enable validate constraint ck_id;

Table altered

SQL> insert into test values(5, 'Oracle');

insert into test values(5, 'Oracle')

ORA-02290:?違反檢查約束條件?(MYHR.CK_ID)

SQL> insert into test values(17,'ERP');

1 row inserted

SQL> commit;

Commit complete

4?測試2: Enable Novalidate

SQL> alter table test disable constraint ck_id;

Table altered

SQL> insert into test values(5, 'Oracle');

1 row inserted

SQL> commit;

Commit complete

SQL> select * from test;

???????????ID NAME

----------- ----------

??????????17 ERP

????????????5 Oracle

?

SQL> alter table test enable novalidate constraint ck_id;

Table altered

SQL> insert into test values(32, 'SAP');

1 row inserted

SQL> insert into test values(3, 'Linux');

insert into test values(3, 'Linux')

ORA-02290:?違反檢查約束條件?(MYHR.CK_ID)

SQL> commit;

Commit complete

5?測試3: Disable Validate

SQL> delete from test where id < 10;

1 row deleted

SQL> commit;

Commit complete

SQL> alter table test disable validate constraint ck_id;

Table altered

SQL> select * from test;

?????????????ID NAME

------------- ----------

?????????????17 ERP

?????????????32 SAP

SQL> update test set name = 'Change' where id = 17;

update test set name = 'Change' where id = 17

ORA-25128:?不能對帶有禁用和驗證約束條件?(MYHR.CK_ID)?的表進行插入/更新/刪除

6?測試4: Disable Novalidate

SQL> alter table test disable novalidate constraint ck_id;

Table altered

SQL> insert into test values(2, 'Linux');

1 row inserted

SQL> insert into test values(13, 'Windows');

1 row inserted

SQL> update test set name = 'Change' where id = 17;

1 row updated

SQL> commit;

Commit complete

SQL> select * from test;

??????????ID NAME

---------- ----------

??????????17 Change

??????????13 Windows

??????????32 SAP

???????????2 Linux

?

總結

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