That's all you have to do to create aforeign key in MySQL, but because MySQL supports multiple database engines (database storage engines), you need to know if your foreign key declaration is really going to do what you think it will. MySQL foreign key support in database engines Laughin...
MySQL官方文档 - 外键约束 通过以上信息,您可以更好地理解MySQL中外键的概念、优势、类型、应用场景以及常见问题的解决方法。 相关搜索: mysql删除foreign key SELECT with foreign key和连接表MYSQL foreign_key_checks needed in a foreign key constraint
foreign key(id) references outTable(id) on delete cascade on update cascade); 说明:把id列设为外键,参照外表outTable的id列,当外键的值删除,本表中对应的列筛除,当外键的值改变,本表中对应的列值改变。 引用自:http://www.cppblog.com/wolf/articles/69089.html 在MySQL 3.23.44版本后,InnoDB引擎类型...
Throughout this section we will use the tables shown in the above figure. First of all, create the tables and add some data: mysql> CREATE DATABASE clusterdb;USE clusterdb; mysql> CREATE TABLE counties (county VARCHAR(30) NOT NULL PRIMARY KEY, country VARCHAR(30)) ENGINE=ndb; mysql> ...
ENGINE = InnoDB MySQL meldet: Dokumentation #1005 - Kann Tabelle `test_apptest`.`#sql-eb0_fd` nicht erzeugen (Fehler: 150 "Foreign key constraint is incorrectly formed") (Details…) In English: #1005 - Cannot create table `test_apptest`.`#sql-eb0_fd` (Error: 150 …)Navigate...
在mysql中MyISAM和InnoDB存储引擎都支持外键(foreign key),但是MyISAM只能支持语法,却不能实际使用。下面通过例子记录下InnoDB中外键的使用方法: 创建主表: mysql> create table parent(id int not null,primary key(id)) engine=innodb; Query OK, 0 rows affected (0.04 sec) ...
PRIMARYKEY(`id`), 12 KEY`dage_id` (`dage_id`), 13 CONSTRAINT`xiaodi_ibfk_1`FOREIGNKEY(`dage_id`)REFERENCES`dage` (`id`) 14 ) ENGINE=InnoDBDEFAULTCHARSET=latin1; 插入个大哥: 1 mysql>insertintodage(name)values('铜锣湾'); 2
mysql> DELETE FROM parent WHERE id = 1; ERROR 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails (`test`.`child`, CONSTRAINT `child_ibfk_1` FOREIGN KEY (`parent_id`) REFERENCES `parent` (`id`)) ...
mysql> alter table busi_table -> add constraint id_check -> foreign key(repo_id) -> references repo_table(repo_id) -> on delete cascade -> on update cascade; --- ENGINE=InnoDB DEFAULT CHARSET=gb2312; //另一种方法,可以替换type=innodb; 3、...
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS; SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS; This results in MySQL 5.6.36-1~dotdeb+7.1 (German) in the following error message: Fehler SQL-Befehl: -- --- -- Table `test_apptest`.`Roles_has_Persons` -- --- CREATE TABLE IF ...