CODEWITHSUNDEEP
mysqlhibernate
Java Developer
Java Developer

Reputation: 1901

Can we define One FOREIGN KEY as more than Two columns in one Table?

This is my Database Table which is giving Error..

Foreign key Define in more then Two columns ..

    CREATE  TABLE IF NOT EXISTS `EC_ATTENDEES` (
  `S_ID` VARCHAR(30) NOT NULL PRIMARY KEY,
  `USER_ID` VARCHAR(30) NULL ,
  `TYPE` VARCHAR(30) NULL ,
`TIMETABLE_ID` VARCHAR(30) NULL ,
  `COURSE_FEE` INT NULL ,
  `PERMISSION` TINYINT(1) NULL ,
  `PAYMENT_STATUS` VARCHAR(30) NULL ,
  `BEGIN_CLASS_NUM` INT NULL ,
  `END_CLASS_NUM` INT NULL ,

    FOREIGN KEY (`USER_ID` ) REFERENCES `EC_USER` (`S_ID` ),
    FOREIGN KEY (`BEGIN_CLASS_NUM` ) REFERENCES `EC_TIMETABLE` (`S_ID` ),
    FOREIGN KEY (`END_CLASS_NUM` ) REFERENCES `EC_TIMETABLE` (`S_ID` ),
    FOREIGN KEY (`TIMETABLE_ID` ) REFERENCES `EC_TIMETABLE` (`S_ID` ));

Upvotes: 0

Views: 87

Answers (2)

imsurya
imsurya

Reputation: 164

It could not possible, your linking is incorrect.

Upvotes: 0

user149341
user149341

Reputation:

It's probably because the type of one of the foreign key columns doesn't match the type of the referenced column. Two of your columns mentioned in the foreign keys (BEGIN_CLASS_NUM and END_CLASS_NUM) have type INT, and the other one (TIMETABLE_ID) has type VARCHAR(30). The referenced column (S_ID) can only possibly be one of the two, so either one or two of the foreign keys will generate errors.

Upvotes: 1

Related Questions