我有2张这样的桌子:
'CREATE TABLE `preoperativeassessments` (
`Id` char(36) NOT NULL,
`SurgeonName` varchar(100) NOT NULL,
`SurgeonExperience` int(11) DEFAULT NULL,
`AnesthetistName` varchar(100) DEFAULT NULL,
`DateOfBirthYear` int(11) DEFAULT NULL,
`Gender` int(11) DEFAULT NULL,
`Status` int(11) DEFAULT NULL,
`SurgeryDate` datetime(6) DEFAULT NULL,
`HospitalId` varchar(20) NOT NULL,
`PatientId` varchar(50) NOT NULL,
`SurgeonId` bigint(20) NOT NULL,
`TheaterId` varchar(16) DEFAULT NULL,
`AssessmentDate` datetime(6) DEFAULT NULL,
`BodyStructureId` int(11) NOT NULL,
`MethodId` varchar(100) DEFAULT NULL,
`EthnicityId` int(11) DEFAULT NULL,
PRIMARY KEY (`Id`),
KEY `FK_PreOperativeAssessments_Hospitals_HospitalId_idx` (`HospitalId`),
KEY `FK_PreOperativeAssessments_Patients_PatientId_idx` (`PatientId`),
KEY `FK_PreOperativeAssessments_Users_SurgeonId_idx` (`SurgeonId`),
KEY `FK_PreOperativeAssessments_BodyStructures_BodyStructureId_idx` (`BodyStructureId`),
CONSTRAINT `FK_PreOperativeAssessments_BodyStructures_BodyStructureId` FOREIGN KEY (`BodyStructureId`) REFERENCES `bodystructures` (`Id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_PreOperativeAssessments_Hospitals_HospitalId` FOREIGN KEY (`HospitalId`) REFERENCES `hospitals` (`Id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_PreOperativeAssessments_Patients_PatientId` FOREIGN KEY (`PatientId`) REFERENCES `patients` (`Id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_PreOperativeAssessments_Users_SurgeonId` FOREIGN KEY (`SurgeonId`) REFERENCES `abpusers` (`Id`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1'
CREATE TABLE `ethnicities` (
`Id` int(11) NOT NULL,
`Description` varchar(100) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
,我尝试使用此方法添加外键约束:
ALTER TABLE casemix.preoperativeassessments ADD CONSTRAINT FK_PreOperativeAssessments_Ethnicities_EthnicityId FOREIGN KEY (EthnicityId) REFERENCES casemix.ethnicities (Id) ON UPDATE NO ACTION ON DELETE CASCADE
但是我一直收到此错误:“错误代码:1215。无法添加外键约束”
这里可能是什么问题?
答案 0 :(得分:1)
'InnoDB允许外键引用任何索引列或一组列。但是,在引用表中,必须有一个索引,其中引用列是相同顺序的第一列。 -https://dev.mysql.com/doc/refman/8.0/en/create-table-foreign-keys.html或主键