MySQL errorno 121

Question

我在MySQL创建中遇到此错误.我正在做:

CREATE TABLE `blogReply` (

    `Id`      INT(24)      NOT NULL AUTO_INCREMENT COMMENT 'Primary Key of This Table',
    `blogId`  INT(24)      NOT NULL COMMENT 'Blog where this reply was posted',
    `userId`  INT(24)      NULL COMMENT 'User the blog was posted by',
    `name`    VARCHAR(100) NULL DEFAULT 'Unknown' COMMENT 'The Name of the user that the reply was posted by',
    `email`   VARCHAR(100) NULL DEFAULT 'Unknown' COMMENT 'The Email of the user that the reply was posted by',
    `http`    VARCHAR(300) NULL DEFAULT 'Unknown' COMMENT 'The Webaddress of the user that the reply was posted by',
    `message` TEXT         NOT NULL COMMENT 'text of the blog',
    `votes`   INT(10)      DEFAULT 0 COMMENT 'Rating of the Blog',
    `ratedBy` TEXT         COMMENT 'People who have already Voted on this blog',
    `dateReg` BIGINT       NOT NULL COMMENT 'Date the User was Registered',

    PRIMARY KEY (`Id`),

    CONSTRAINT `FK_userId` FOREIGN KEY(`userId`)
        REFERENCES `user` (`Id`)
        ON DELETE SET NULL
        ON UPDATE CASCADE,

    CONSTRAINT `FK_blogId` FOREIGN KEY(`blogId`)
        REFERENCES `blog` (`Id`)
        ON DELETE CASCADE
        ON UPDATE CASCADE

) ENGINE = InnoDB;

有任何想法吗？错误状态:Can't create table './xxxxxxxx/blogReply.frm' (errno: 121)

Answer 1

检查所有约束是否确实拼写正确,还检查是否有任何其他表使用约束名称FK_userId或FK_blogId

Answer 2

错误121是外键约束问题.首先要检查的是你的外键定义是否正确(所有表和字段名称都是正确的,等等).

您也可以在创建表之前尝试禁用外键检查,如下所示:

SET FOREIGN_KEY_CHECKS = 0;

当你重新启用密钥检查(将其设置为1)时,这会产生向下抛出错误的缺点,但是,如果是这种情况,那么这意味着你在某处干扰了创建外键的某些无效记录.

但是,如果您手动移动数据库文件(例如物理重命名data/your_database_name目录),也会发生此问题.InnoDB无法将类似物理变化与表空间相关联,因此它与内部结构混杂在一起.

如果这是您所做的,那么最有效的解决方案是将旧数据库移回原来的位置,转储或导出它,然后DROP DATABASE在重新导入之前对其进行处理.