CREATE TABLE `fitness_pledges` (
`ID` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`first_name` VARCHAR(250) NOT NULL,
`last_name` VARCHAR(250) NOT NULL,
`email` VARCHAR(100) NOT NULL,
`token` BIGINT(20) UNSIGNED NOT NULL,
`email_valid` TINYINT(1) UNSIGNED NOT NULL DEFAULT '0',
`entered_sweeps` TINYINT(1) UNSIGNED NOT NULL DEFAULT '0',
`referrals` INT(10) UNSIGNED NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
UNIQUE INDEX `email` (`email`),
UNIQUE INDEX `token` (`token`)
)
COMMENT='holds validation token, first name, last name, email address, number of referrals and whether sweepstakes was entered\r\n'
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
;
CREATE TABLE `finess_referrals` (
`ID` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`first_name` VARCHAR(250) NOT NULL,
`last_name` VARCHAR(250) NOT NULL,
`email` VARCHAR(100) NOT NULL,
`token` BIGINT(20) UNSIGNED NOT NULL,
`referral_token` BIGINT(20) UNSIGNED NOT NULL,
`referral_validated` TINYINT(4) NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
INDEX `token_FK` (`token`),
INDEX `referral_token_FK` (`referral_token`),
CONSTRAINT `referral_token_FK` FOREIGN KEY (`referral_token`) REFERENCES `fitness_pledges` (`token`) ON DELETE NO ACTION,
CONSTRAINT `token_FK` FOREIGN KEY (`token`) REFERENCES `fitness_pledges` (`token`) ON DELETE NO ACTION
)
COMMENT='holds the first name, last name, email and validation token of the referrer as well as the token of the referred individual and a flag for whether the referred individual\'s email has been validated'
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB
;
这个由 HeidiSQL 生成的 Alter Table 尝试为组合的 first_name、last_name 和 email 字段添加外键失败,外键约束形成不正确。字段都定义相同,排序规则相同。为什么会失败?
ALTER TABLE `finess_referrals`
ADD CONSTRAINT `first_last_email_FK` FOREIGN KEY (`first_name`, `last_name`, `email`)
REFERENCES `fitness_pledges` (`first_name`, `last_name`, `email`) ON DELETE NO ACTION;