MySQL Error number: 3941; Symbol: ER_ALTER_CONSTRAINT_ENFORCEMENT_NOT_SUPPORTED; SQLSTATE: HY000

文档解释

Error number: 3941; Symbol: ER_ALTER_CONSTRAINT_ENFORCEMENT_NOT_SUPPORTED; SQLSTATE: HY000

Message: Altering constraint enforcement is not supported for the constraint ‘%s’. Enforcement state alter is not supported for the PRIMARY, UNIQUE and FOREIGN KEY type constraints.

ER_ALTER_CONSTRAINT_ENFORCEMENT_NOT_SUPPORTED 错误号:3941,SQLSTATE:HY000

错误说明:

ER_ALTER_CONSTRAINT_ENFORCEMENT_NOT_SUPPORTED 错误号:3941,SQLSTATE:HY000 错误消息是MySQL的一种常见的错误,该错误发生时,表示ALTER TABLE语句试图边调整一个约束的启用/禁用,但MySQL不支持这样的约束调整。

常见案例

例如,下面的语句试图强制禁用一个叫做my_idx的索引:

ALTER TABLE t1 ALGORITHM=INPLACE,LOCK=NONE DISABLE KEYS my_idx;

然而,上述语句会导致以下错误:

ERROR 3941 (HY000): Alter table with ALGORITHM=INPLACE,LOCK=NONE is not supported for altering constraint enforcement. Try ALGORITHM=COPY.

解决方法:

要解决这个错误,可以使用COPY算法,而不是INPLACE算法。因此,要解决上面的错误,只需更改语句,将ALGORITHM=INPLACE替换为ALGORITHM=COPY,然后再次尝试。

ALTER TABLE t1 ALGORITHM=COPY,LOCK=NONE DISABLE KEYS my_idx;

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