SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; 示例: mysql> CREATE TABLE child ( -> id INT(10) NOT NULL PRIMARY KEY, -> parent_id INT(10), -> FOREIGN KEY (parent_id) REFERENCES `parent`(`id`) -> ) ENGINE INNODB; ERROR 1215 (HY000): Cannot add foreign key constraint # ...
ERROR1215(HY000): Cannotaddforeignkeyconstraint 首先想到可能类型不同,于是查看表结构 mysql>desccustomers_info;+---+---+---+---+---+---+|Field|Type|Null|Key|Default|Extra|+---+---+---+---+---+---+|c_num|int(10) unsigned|NO|PRI|0|||c_name|varchar(70)|YES||NULL|||c_b...
Mysql foreign key 不能添加常见原因: 1.检查目标指向的字段是否是主键。 2.检查是否表内已经存有数据,导致约束失败 5.检查是否重建了同名的索引,比如第一次建立失败,再次建立可能会因为索引重复导致失败 6.可以设置一下 ON DELETE SET NULL ON UPDATE RESTR...
ERROR 1822 (HY000): Failed to add the foreign key constraint. Missing index for constraint ‘orderitem_ibfk_1’ in the referenced table ‘orders’ MySQL报这个错时去检查外键设置!!!这个外键是不是另外一个表的主键 设置外键的时候需要注意以下几点: (1)外键是用于两个表的数据之间建立连接,可以是一列...
PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; 外键是,article.category_id 关联 category.id ; 出错的原因在于2个字段的int的类型不同,article.category_id 有 unsigned 属性,而 category.id 没有这个属性。 最终category表的结构如下: CREATE ...
also permits fast access to data when the primary key is used in queries. If a primary key constraint is defined on more than one column, values can be duplicated within one column, but each combination of values from all the columns in the primary key constraint definition must be unique....
also permits fast access to data when the primary key is used in queries. If a primary key constraint is defined on more than one column, values can be duplicated within one column, but each combination of values from all the columns in the primary key constraint definition must be unique....
执行:alter table Taco add foreign key (taco_order) references Taco_Order(id);时出现Cannot add foreign key constraint。 发现taco_order 这个数据类型为bigint。即:主键,外键类型不一致无法添加外键。 修改为: taco_order int(11) not null 之后,再次执行添加外键成功。
[CONSTRAINTconstraint_name]{PRIMARYKEY|UNIQUE}(column_name)[NOTENFORCED[ENABLEQUERYOPTIMIZATION|DISABLEQUERYOPTIMIZATION]|ENFORCED] Parameter Description IF NOT EXISTS Does not throw an error if a table with the same name exists. A notice is issued in this case. ...
SQL> insert into bowie_kid values (1000002, 'HEROES', 1); insert into bowie_kid values (1000002, 'HEROES', 1) * ERROR at line 1: ORA-02291: integrity constraint (BOWIE.BOWIE_KID_FK) violated - parent key not found And we notice with a fresh block dump that the index entry has be...