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关于约束ENABLE NOVALIDATE的一个疑问




CREATE TABLE test
(id varchar2(12),
name varchar2(30) ,CONSTRAINT pk_test PRIMARY k

ALTER TABLE test disable CONSTRAINT pk_test


然后向表中插入两条完全一样的数据并commit

我的印象是ENABLE NOVALIDATE并不检查已经存在的数




SQL> ALTER TABLE test enable novalidate constra
ALTER TABLE test enable novalidate CONSTRAINT p
*
ERROR 位于第 1 行:
ORA-02437: 无法验证 (DBO.PK_TEST) - 违反主键


参考hrb_qiuyb文章




SQL> CREATE TABLE t(a INT,b varchar2(20));

TABLE created.

SQL> INSERT INTO t VALUES(1,'lijie');

1 ROW created.

SQL> ALTER TABLE t ADD constraints pk_t_a PRIMARY KEY(a);

TABLE altered.

SQL> SELECT constraint_name,constraint_type,STATUS FROM user_constraints
WHERE TABLE_NAME='T';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
PK_T_A                         P ENABLED

SQL> SELECT index_name,uniqueness FROM user_indexes WHERE TABLE_NAME='T';

INDEX_NAME                     UNIQUENES
------------------------------ ---------
PK_T_A                         UNIQUE

SQL> ALTER TABLE t disable constraints pk_t_a;

TABLE altered.

SQL> SELECT constraint_name,constraint_type,STATUS FROM user_constraints
WHERE TABLE_NAME='T';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
PK_T_A                         P DISABLED
SQL> SELECT index_name,uniqueness FROM user_indexes WHERE TABLE_NAME='T';

no ROWS selected

SQL> INSERT INTO t VALUES(1,'tina');

1 ROW created.

SQL> ALTER TABLE t enable novalidate constraints pk_t_a;
ALTER TABLE t enable novalidate constraints pk_t_a
*
ERROR at line 1:
ORA-02437: cannot validate (TAOBAO.PK_T_A) - PRIMARY KEY violated


这里问题是：primary key所依赖的唯一键索引起的.

解决方法：




SQL> CREATE TABLE t2 AS (SELECT * FROM t WHERE 1=0);

TABLE created.

SQL> CREATE INDEX ind_t2_a ON t2(a);

INDEX created.

SQL> INSERT INTO t2 VALUES(1,'lijie');

1 ROW created.

SQL> ALTER TABLE t2 ADD constraints pk_t2_a PRIMARY KEY(a);

TABLE altered.

SQL> SELECT constraint_name,constraint_type,STATUS FROM user_constraints
WHERE TABLE_NAME='T2';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
PK_T2_A                        P ENABLED

SQL> SELECT index_name,uniqueness FROM user_indexes WHERE TABLE_NAME='T2';

INDEX_NAME                     UNIQUENES
------------------------------ ---------
IND_T2_A                       NONUNIQUE

SQL> ALTER TABLE t2 disable constraints pk_t2_a;

TABLE altered.

SQL> SELECT constraint_name,constraint_type,STATUS FROM user_constraints
WHERE TABLE_NAME='T2';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
PK_T2_A                        P DISABLED

SQL> SELECT index_name,uniqueness FROM user_indexes WHERE TABLE_NAME='T2';

INDEX_NAME                     UNIQUENES
------------------------------ ---------
IND_T2_A                       NONUNIQUE

SQL> INSERT INTO t2 VALUES(1,'tina');

1 ROW created.

SQL> ALTER TABLE t2 enable validate  constraints pk_t2_a;
ALTER TABLE t2 enable validate  constraints pk_t2_a
*
ERROR at line 1:
ORA-02437: cannot validate (TAOBAO.PK_T2_A) - PRIMARY KEY violated
SQL> ALTER TABLE t2 enable novalidate constraints pk_t2_a;

TABLE altered.

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