码迷,mamicode.com
首页 > 数据库 > 详细

MySQL 外键索引不生效

时间:2019-10-05 22:35:57      阅读:186      评论:0      收藏:0      [点我收藏+]

标签:default   current   const   monitor   constrain   state   from   就会   variable   

mysql> create table department (
    ->
    ->   id int primary key auto_increment,
    ->   dep_name varchar(30),
    ->   dep_location varchar(30)
    ->
    -> )charset utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> create table emp (
    ->
    ->   id int primary key auto_increment,
    ->   name varchar(30),
    ->   age int,
    ->   dep_id int,
    ->   CONSTRAINT emp_dep_fk foreign key (dep_id) references department(id)
    -> )charset utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into emp (name, age, dep_id) values ("张三", 20, 1);
Query OK, 1 row affected, 2 warnings (0.00 sec)

mysql> select * from emp;
+----+------+------+--------+
| id | name | age  | dep_id |
+----+------+------+--------+
|  1 |      |   20 |      1 |
+----+------+------+--------+
1 row in set (0.00 sec)

 

外键没有起作用, 经查看发现:

mysql>  show variables like %storage_engine%;
+------------------------+--------+
| Variable_name          | Value  |
+------------------------+--------+
| default_storage_engine | MyISAM |
| storage_engine         | MyISAM |
+------------------------+--------+
2 rows in set (0.00 sec)

 

使用的引擎是MyISAM. 将其设置为InnoDB. 



mysql> set default_storage_engine="InnoDB" -> ; Query OK, 0 rows affected (0.00 sec)

mysql> show variables like ‘%storage_engine%‘;            -- 这个只是临时设置, 当数据库断开重新链接后就会变会MyISAM
+------------------------+--------+
| Variable_name | Value |
+------------------------+--------+
| default_storage_engine | InnoDB |
| storage_engine | InnoDB |
+------------------------+--------+
2 rows in set (0.00 sec)

 

将MySQL的引擎持久的改成InnoDB

 

修改My.ini:  default-storage-engine=INNODB   重新数据库

 

 

C:\Users\Administrator.DESKTOP-UHUP1G8>mysql -uroot -p
Enter password: ****
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.53 MySQL Community Server (GPL)

Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

mysql> show variables like ‘%storage_engine%‘;
+------------------------+--------+
| Variable_name | Value |
+------------------------+--------+
| default_storage_engine | InnoDB |
| storage_engine | InnoDB |
+------------------------+--------+
2 rows in set (0.00 sec)

 

这样在从写登录进来后也是InnoDB了

 

MySQL 外键索引不生效

标签:default   current   const   monitor   constrain   state   from   就会   variable   

原文地址:https://www.cnblogs.com/exp0it/p/11625841.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!