在 phpMyAdmin 中消失的外键

我正在 mysql 中创建一个新表，并尝试向其中一个字段添加外键约束.

<前>创建表`在线订单`(`receiptid` varchar(10) NOT NULL 默认值 '',`delivereddate` 日期默认为 NULL，`cid` int(10) 非空，`card#` int(10) 默认为 NULL，`expire` 日期默认为 NULL，主键(`receiptid`)，FOREIGN KEY (receiptid) REFERENCES 购买) 引擎=MyISAM 默认字符集=latin1;

但是，在它创建之后，我进入 phpMyAdmin 并导出表.外键约束似乎已经消失了.

<前>创建表`在线订单`(`receiptid` varchar(10) NOT NULL 默认值 '',`delivereddate` 日期默认为 NULL，`cid` int(10) 非空，`card#` int(10) 默认为 NULL，`expire` 日期默认为 NULL，主键(`receiptid`)) 引擎=MyISAM 默认字符集=latin1;

phpMyAdmin 是否去掉了外键，还是我在这里做错了什么?

解决方案

需要使用InnoDB引擎才能有外键.

参考:http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.html

I am creating a new table inside mysql and I am trying to add a foreign key constraint to one of the fields.

CREATE TABLE `onlineorder` (
  `receiptid` varchar(10) NOT NULL default '',
  `delivereddate` date default NULL,
  `cid` int(10) NOT NULL,
  `card#` int(10) default NULL,
  `expire` date default NULL,
  PRIMARY KEY  (`receiptid`),
  FOREIGN KEY (receiptid) REFERENCES purchase
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

However, after it creates it, I go into phpMyAdmin and export the table. and it seems like the foreign key constraint has disappeared.

CREATE TABLE `onlineorder` (
  `receiptid` varchar(10) NOT NULL default '',
  `delivereddate` date default NULL,
  `cid` int(10) NOT NULL,
  `card#` int(10) default NULL,
  `expire` date default NULL,
  PRIMARY KEY  (`receiptid`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;

Does phpMyAdmin get rid of foreign keys or am I doing something wrong here?

解决方案

You need to use the InnoDB engine to have foreign keys.

Ref: http://dev.mysql.com/doc/refman/5.0/en/innodb-foreign-key-constraints.html