I have a table RESERVATIONS, which has these Constraints:

CONSTRAINT `reservations_customerID` FOREIGN KEY (`customer_id`) REFERENCES `customers` (`customer_id`),

CONSTRAINT `reservations_eventID` FOREIGN KEY (`event_id`) REFERENCES `events` (`event_id`),

CONSTRAINT `reservations_hotelID` FOREIGN KEY (`hotel_id`) REFERENCES `hotels` (`hotel_id`)

For some reason, this INSERT SUCCEEDS:
INSERT INTO reservations (hotel_id, customer_id) VALUES (111,222)

While this INSERT FAILS:
INSERT INTO reservations (hotel_id, event_id, customer_id) VALUES (111,222,333)

With the following error message:
"Cannot add or update a child row: a foreign key constraint fails ('turon/reservations', CONSTRAINT 'reservations_eventID' FOREIGN KEY ('event_id') REFERENCES 'events' ('event_id'))

As far as I can tell all constraints are similar.

Any suggestions?

Thanks,
Michael

the error message is quite clearly telling you that you do not have a 222 row in the events table

Oh! So a Foreign Key Constraint also prevents you from entering a non-existent FK value?

Shoot! I thought FK Constraints we only to prevent deleting a related record...

Is that correct?

Thanks, Michael

that is correct

Living and learning. Thanks for the help, r937.

All the best,

Michael