我正在尝试做的事情我已经做了无数次,但现在从 MySql 5.6.26 升级到 5.6.27 失败了(在 5.7.x 中也失败了)。我有一个数据库,其中包含一堆具有外键约束的表。我已导出(使用 phpMyAdmin)替换表,指定了以下导出选项:
Disable foreign key checks
Add DROP TABLE / VIEW / PROCEDURE / FUNCTION / EVENT / TRIGGER statement
Add CREATE TABLE statement
生成的导出文件部分包含:
SET FOREIGN_KEY_CHECKS=0;
DROP TABLE IF EXISTS `application`;
CREATE TABLE `application` (
`PK_Application` int(11) NOT NULL,
`FK_Parent` int(11) DEFAULT NULL,
`ApplicationLevel` tinyint(4) NOT NULL,
`Description` varchar(35) NOT NULL,
`Sequence` tinyint(4) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=latin1;
. . .
. . .
DROP TABLE IF EXISTS `product_x_application`;
CREATE TABLE `product_x_application` (
`PK_Product_X_Application` int(11) NOT NULL,
`Product_PKID` varchar(36) NOT NULL,
`FK_Application` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
. . .
. . .
ALTER TABLE `product_x_application`
ADD CONSTRAINT `product_x_application_ibfk_2` FOREIGN KEY (`FK_Application`) REFERENCES `application` (`PK_Application`) ON DELETE CASCADE ON UPDATE CASCADE;
当此文件输入到 mysql.exe 或表已存在时的 phpMyAdmin 导入函数时,表application
的product_x_application
DROP 语句application
成功,但随后的 CREATE TABLE 语句失败,并显示:
ERROR 1215 (HY000): 无法添加外键约束
但是,如果我首先删除具有引用 tableproduct_x_application
的外键约束的表,则 CREATE TABLE 语句会成功。product_x_application_ibfk_2
application
从那以后,我了解了更多信息。我走到我的生产机器上,它运行带有 MySql 5.5 服务器和 phpMyAdmin 4.4.23 phpMyAdmin 的 Linux,并且只导出了两个有问题的表,并且能够将生成的文件导入我的 MySql 5.6.27 服务器. 这是两个完整的导出文件(仅结构)。首先来自有问题的 5.6.27 服务器:
-- phpMyAdmin SQL Dump
-- version 4.4.15
-- http://www.phpmyadmin.net
--
-- Host: localhost
-- Generation Time: Jan 10, 2016 at 07:01 AM
-- Server version: 5.6.26-log
-- PHP Version: 5.6.12
SET FOREIGN_KEY_CHECKS=0;
SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";
/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8mb4 */;
--
-- Database: `spmorell_sami`
--
-- --------------------------------------------------------
--
-- Table structure for table `application`
--
DROP TABLE IF EXISTS `application`;
CREATE TABLE `application` (
`PK_Application` int(11) NOT NULL,
`FK_Parent` int(11) DEFAULT NULL,
`ApplicationLevel` tinyint(4) NOT NULL,
`Description` varchar(35) NOT NULL,
`Sequence` tinyint(4) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
-- --------------------------------------------------------
--
-- Table structure for table `product_x_application`
--
DROP TABLE IF EXISTS `product_x_application`;
CREATE TABLE `product_x_application` (
`PK_Product_X_Application` int(11) NOT NULL,
`Product_PKID` varchar(36) NOT NULL,
`FK_Application` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
--
-- Indexes for dumped tables
--
--
-- Indexes for table `application`
--
ALTER TABLE `application`
ADD PRIMARY KEY (`PK_Application`);
--
-- Indexes for table `product_x_application`
--
ALTER TABLE `product_x_application`
ADD PRIMARY KEY (`PK_Product_X_Application`),
ADD KEY `Product_PKID` (`Product_PKID`),
ADD KEY `FK_Application` (`FK_Application`);
--
-- AUTO_INCREMENT for dumped tables
--
--
-- AUTO_INCREMENT for table `application`
--
ALTER TABLE `application`
MODIFY `PK_Application` int(11) NOT NULL AUTO_INCREMENT;
--
-- AUTO_INCREMENT for table `product_x_application`
--
ALTER TABLE `product_x_application`
MODIFY `PK_Product_X_Application` int(11) NOT NULL AUTO_INCREMENT;
--
-- Constraints for dumped tables
--
--
-- Constraints for table `product_x_application`
--
ALTER TABLE `product_x_application`
ADD CONSTRAINT `product_x_application_ibfk_1` FOREIGN KEY (`Product_PKID`) REFERENCES `product` (`Product_PKID`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD CONSTRAINT `product_x_application_ibfk_2` FOREIGN KEY (`FK_Application`) REFERENCES `application` (`PK_Application`) ON DELETE CASCADE ON UPDATE CASCADE;
SET FOREIGN_KEY_CHECKS=1;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
请注意,表的主键application
是在 ALTER TABLE 语句中定义的。这是从 5.5 服务器导出的文件:
-- phpMyAdmin SQL Dump
-- version 3.5.8.2
-- http://www.phpmyadmin.net
--
-- Host: localhost
-- Generation Time: Jan 10, 2016 at 05:09 AM
-- Server version: 5.5.42-37.1-log
-- PHP Version: 5.4.23
SET FOREIGN_KEY_CHECKS=0;
SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";
--
-- Database: `spmorell_sami`
--
-- --------------------------------------------------------
--
-- Table structure for table `application`
--
DROP TABLE IF EXISTS `application`;
CREATE TABLE `application` (
`PK_Application` int(11) NOT NULL AUTO_INCREMENT,
`FK_Parent` int(11) DEFAULT NULL,
`ApplicationLevel` tinyint(4) NOT NULL,
`Description` varchar(35) NOT NULL,
`Sequence` tinyint(4) NOT NULL,
PRIMARY KEY (`PK_Application`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=15 ;
-- --------------------------------------------------------
--
-- Table structure for table `product_x_application`
--
DROP TABLE IF EXISTS `product_x_application`;
CREATE TABLE `product_x_application` (
`PK_Product_X_Application` int(11) NOT NULL AUTO_INCREMENT,
`Product_PKID` varchar(36) NOT NULL,
`FK_Application` int(11) NOT NULL,
PRIMARY KEY (`PK_Product_X_Application`),
KEY `Product_PKID` (`Product_PKID`),
KEY `FK_Application` (`FK_Application`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1633 ;
--
-- Constraints for dumped tables
--
--
-- Constraints for table `product_x_application`
--
ALTER TABLE `product_x_application`
ADD CONSTRAINT `product_x_application_ibfk_2` FOREIGN KEY (`FK_Application`) REFERENCES `application` (`PK_Application`) ON DELETE CASCADE ON UPDATE CASCADE,
ADD CONSTRAINT `product_x_application_ibfk_1` FOREIGN KEY (`Product_PKID`) REFERENCES `product` (`Product_PKID`) ON DELETE CASCADE ON UPDATE CASCADE;
SET FOREIGN_KEY_CHECKS=1;
这里表的主键是在application
定义表时立即定义的。我认为问题在于,product_x_application
在系统尝试重新创建application
表时已经存在的表具有对表的外键约束,当重新创建时,该表在外键上没有所需的索引,因为主密钥尚未定义。