MySQL foreign key support in database engines MySQL foreign keys and ON UPDATE and ON DELETE MySQL foreign key FAQ: How do I define a foreign key in MySQL? Answer: Here's a quick example of how I typically define a foreign key in MySQL. Diving right into an example, here's the defin...
select table_name,column_name,column_type,column_key,column_comment from information_schema.Columns where table_schema=‘Db’
) ENGINE=INNODBDEFAULTCHARSET=latin1;CREATETABLE`xiaodi` ( `id`INT(11)NOTNULLauto_increment, `dage_id`INT(11)DEFAULTNULL, `name`VARCHAR(32)DEFAULT'',PRIMARYKEY(`id`),KEY`dage_id` (`dage_id`),CONSTRAINT`xiaodi_ibfk_1`FOREIGNKEY(`dage_id`)REFERENCES`dage` (`id`) ) ENGINE=INNODBDEFAULT...
mysql> CREATE TABLE slave (cust_id int(11),cust_name int(11),cust_email char(255),cust_address char(50),PRIMARY KEY(cust_id),CONSTRAINT call_name FOREIGN KEY(cust_name) REFERENCES master(cust_id));Query OK, 0 rows affected (0.04 sec)重新创建slave数据表。注意！cust_name字段熟悉为int...
Note:当然如果一定要这样做,可以这样 SETforeign_key_checks=0;-- Drop tablesdroptable...-- Drop viewsdropview...SETforeign_key_checks=1; NO ACTION 这是一个来自SQL标准的关键字,在mysql中和上面的RESTRICT相同 SET DEFAULT 设置为默认值
mysql外键(foreign key)的用法 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;...
FOREIGN KEY (FK) 标识该字段为该表的外键,实现表与表之间的关联 NULL 标识是否允许为空,默认为NULL。 NOT NULL 标识该字段不能为空,可以修改。 UNIQUE KEY (UK) 标识该字段的值是唯一的,可以为空,一个表中可以有多个UNIQUE KEY AUTO_INCREMENT 标识该字段的值自动增长(整数类型,而且为主键) ...
repo_id char(13) not null primary key, repo_name char(14) not null) type=innodb; 创建表2 mysql> create table busi_table( -> busi_id char(13) not null primary key, -> busi_name char(13) not null, -> repo_id char(13) not null, ...
For storage engines that do not support foreign keys (such as MyISAM), MySQL Server parses and ignores foreign key specifications. MySQL parses but ignores “inline REFERENCES specifications” (as defined in the SQL standard) where the references are defined as part of the column specification...
然后再设置外键约束: SET FOREIGN_KEY_CHECKS=1; 2. MySQL 5.1.48 导入 MySQL 5.7.18 时遇到 T FOREIGN_KEY_CHECKS = 0 错误的解决方法 #1064 – You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘T FOREIGN...