MySQL错误1451

命令：

DELETE FROM  `meetings`.`meetingparticipants` WHERE  `meetingparticipants`.`idParticipants` =503 AND  `meetingparticipants`.`idMeetings` =83

我知道我的数据库中有一个简单的错误。我试图从会议参与者表中删除一行，并收到以下错误：

#1451 - Cannot delete or update a parent row: a foreign key constraint fails (`meetings`.`invoices`, CONSTRAINT `fk_meetingid` FOREIGN KEY (`fk_meetingid`) REFERENCES `meetingparticipants` (`idMeetings`) ON DELETE NO ACTION ON UPDATE NO ACTION) 

有什么想法吗？我想我需要在参与者表和会议参与者表之间建立外键关系并进行更新，但我更愿意确认或查看是否有任何建议

CREATE TABLE IF NOT EXISTS `invoices` (
  `idinvoices` int(11) NOT NULL AUTO_INCREMENT,
  `fk_invoiceType` int(11) DEFAULT NULL,
  `DocNum` varchar(10) DEFAULT NULL,
  `DZ` varchar(9) DEFAULT NULL,
  `Amount` decimal(10,2) DEFAULT NULL,
  `fk_meetingid` int(11) DEFAULT NULL,
  `fk_participantid` int(11) DEFAULT NULL,
  `invoiceNotes` varchar(255) DEFAULT NULL,
  `invoiceDocuments` blob,
  PRIMARY KEY (`idinvoices`),
  UNIQUE KEY `DOC_Num` (`DocNum`),
  KEY `fk_invoiceType` (`fk_invoiceType`),
  KEY `fk_meetingid` (`fk_meetingid`),
  KEY `fk_participantid` (`fk_participantid`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1014 ;

-- --------------------------------------------------------

--
-- Table structure for table `invoicestatus`
--

CREATE TABLE IF NOT EXISTS `invoicestatus` (
  `idinvoiceStatus` int(11) NOT NULL AUTO_INCREMENT,
  `invoiceStatus` varchar(45) NOT NULL,
  PRIMARY KEY (`idinvoiceStatus`),
  UNIQUE KEY `invoiceStatus_UNIQUE` (`invoiceStatus`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=23 ;

-- --------------------------------------------------------

--
-- Table structure for table `invoicestatushistory`
--

CREATE TABLE IF NOT EXISTS `invoicestatushistory` (
  `fk_invoiceStatus` int(11) DEFAULT NULL,
  `statusStamp` datetime DEFAULT NULL,
  `fk_idinvoices` int(11) NOT NULL,
  `idinvoiceStatusHistory` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`idinvoiceStatusHistory`,`fk_idinvoices`),
  KEY `invoiceStatusHistory` (`fk_invoiceStatus`),
  KEY `invoiceid` (`fk_idinvoices`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1015 ;

-- --------------------------------------------------------

--
-- Table structure for table `invoicetypes`
--

CREATE TABLE IF NOT EXISTS `invoicetypes` (
  `idinvoiceTypes` int(11) NOT NULL AUTO_INCREMENT,
  `invoiceType` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`idinvoiceTypes`),
  UNIQUE KEY `invoiceType_UNIQUE` (`invoiceType`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=21 ;

-- --------------------------------------------------------

--
-- Table structure for table `meetingparticipants`
--

CREATE TABLE IF NOT EXISTS `meetingparticipants` (
  `idParticipants` int(11) NOT NULL,
  `idMeetings` int(11) NOT NULL,
  `invited` tinyint(1) DEFAULT NULL,
  `attended` tinyint(1) DEFAULT NULL,
  `travelCostsReimbursed` tinyint(1) DEFAULT NULL,
  `ParticipantFeeEligible` tinyint(1) DEFAULT NULL,
  `ParticipantFeeProcessed` tinyint(1) DEFAULT NULL,
  PRIMARY KEY (`idParticipants`,`idMeetings`),
  KEY `idParticipants` (`idParticipants`),
  KEY `idMeetings` (`idMeetings`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

-- --------------------------------------------------------

--
-- Table structure for table `meetings`
--

CREATE TABLE IF NOT EXISTS `meetings` (
  `idmeetings` int(11) NOT NULL AUTO_INCREMENT,
  `meetingName` varchar(45) NOT NULL,
  `beginDate` date DEFAULT NULL,
  `endDate` date DEFAULT NULL,
  `location` varchar(45) DEFAULT NULL,
  `meetingNotes` varchar(255) DEFAULT NULL,
  `meetingDocuments` blob,
  `fk_programID` int(110) DEFAULT NULL,
  PRIMARY KEY (`idmeetings`),
  UNIQUE KEY `meetingName_UNIQUE` (`meetingName`),
  KEY `programid` (`fk_programID`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=85 ;

-- --------------------------------------------------------

--
-- Table structure for table `participants`
--

CREATE TABLE IF NOT EXISTS `participants` (
  `idparticipants` int(11) NOT NULL AUTO_INCREMENT,
  `firstName` varchar(45) DEFAULT NULL,
  `lastName` varchar(45) NOT NULL,
  `preferredName` varchar(75) DEFAULT NULL,
  `email` varchar(45) DEFAULT NULL,
  `affiliation` varchar(45) DEFAULT NULL,
  `foreignNational` tinyint(1) DEFAULT NULL,
  `grantPaid` tinyint(1) DEFAULT NULL,
  `bannerid` varchar(9) DEFAULT NULL,
  `participantNotes` varchar(255) DEFAULT NULL,
  `participantDocuments` blob,
  `visaType` int(11) DEFAULT NULL,
  PRIMARY KEY (`idparticipants`),
  UNIQUE KEY `bannerid_UNIQUE` (`bannerid`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=507 ;

-- --------------------------------------------------------

--
-- Table structure for table `programs`
--

CREATE TABLE IF NOT EXISTS `programs` (
  `idprograms` int(11) NOT NULL AUTO_INCREMENT,
  `ProgramName` varchar(45) NOT NULL,
  PRIMARY KEY (`idprograms`),
  UNIQUE KEY `ProgramName_UNIQUE` (`ProgramName`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=21 ;

-- --------------------------------------------------------

--
-- Table structure for table `users`
--

CREATE TABLE IF NOT EXISTS `users` (
  `userID` int(11) NOT NULL AUTO_INCREMENT,
  `userName` varchar(25) NOT NULL,
  `userPassword` varchar(10) NOT NULL DEFAULT 'password',
  `userLevel` int(11) NOT NULL,
  PRIMARY KEY (`userID`),
  UNIQUE KEY `userName` (`userName`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;

-- --------------------------------------------------------

--
-- Table structure for table `visatypes`
--

CREATE TABLE IF NOT EXISTS `visatypes` (
  `idvisaTypes` int(11) NOT NULL AUTO_INCREMENT,
  `visaType` varchar(45) DEFAULT NULL,
  `paymentInstructions` varchar(500) DEFAULT NULL,
  PRIMARY KEY (`idvisaTypes`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;

--
-- Constraints for dumped tables
--

--
-- Constraints for table `invoices`
--
ALTER TABLE `invoices`
  ADD CONSTRAINT `fk_invoiceType` FOREIGN KEY (`fk_invoiceType`) REFERENCES `invoicetypes` (`idinvoiceTypes`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `fk_meetingid` FOREIGN KEY (`fk_meetingid`) REFERENCES `meetingparticipants` (`idMeetings`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `fk_participantid` FOREIGN KEY (`fk_participantid`) REFERENCES `meetingparticipants` (`idParticipants`) ON DELETE NO ACTION ON UPDATE NO ACTION;

--
-- Constraints for table `invoicestatushistory`
--
ALTER TABLE `invoicestatushistory`
  ADD CONSTRAINT `invoiceid` FOREIGN KEY (`fk_idinvoices`) REFERENCES `invoices` (`idinvoices`) ON DELETE NO ACTION ON UPDATE CASCADE,
  ADD CONSTRAINT `invoiceStatusHistory` FOREIGN KEY (`fk_invoiceStatus`) REFERENCES `invoicestatus` (`idinvoiceStatus`) ON DELETE NO ACTION ON UPDATE CASCADE;

--
-- Constraints for table `meetings`
--
ALTER TABLE `meetings`
  ADD CONSTRAINT `programid` FOREIGN KEY (`fk_programID`) REFERENCES `programs` (`idprograms`) ON DELETE NO ACTION ON UPDATE NO ACTION;

---

在名为“fk_meetingid”的

发票

表上有一个外键约束，但引用了

会议参与者

表，该表是一个关联表。在我看来，如果发票链接到会议，它应该直接链接到

会议

表。

手册：

无操作：标准SQL中的关键字。在MySQL中，相当于 限制InnoDB拒绝父级的删除或更新操作 表中是否存在相关的外键值。 有些数据库系统有延迟检查，不执行任何操作都是错误的 延期支票。在MySQL中，检查外键约束 立即，因此没有操作与限制相同

---

如果我理解您的模式（看了30秒后不太可能），您可能希望使用DELETE CASCADE上的

，以便在删除参与者时删除参与者发票。如果您需要保留发票但删除了参与者，请在delete SET NULL上选择

我拥有的是参与者表、会议表和发票表。因为，一个参与者可能会参加一个或多个会议，并且一个会议可能有一个或多个参与者。因此，会议参与者的交叉表。每个参与者可能也会收到一张或多张发票。谢谢……我想这就是问题所在，我将在发票表中查找链接到该参与者的发票，手动删除，然后尝试您的想法——我相信它解决了问题。。。