Hi; mysql> alter table Flights type=InnoDB; Query OK, 1 row affected, 1 warning (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0
mysql> alter table Flights add pilot_id int not null; Query OK, 1 row affected (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> alter table Flights add foreign key (pilot_id) references Pilots (id); ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`seaflight/#sql-4d89_3ac`, CONSTRAINT `#sql-4d89_3ac_ibfk_1` FOREIGN KEY (`pilot_id`) REFERENCES `Pilots` (`id`)) mysql> alter table Pilots type=InnoDB; Query OK, 1 row affected, 1 warning (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 mysql> alter table Flights add foreign key (pilot_id) references Pilots (id); ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`seaflight/#sql-4d89_3ac`, CONSTRAINT `#sql-4d89_3ac_ibfk_1` FOREIGN KEY (`pilot_id`) REFERENCES `Pilots` (`id`)) mysql> describe Pilots; +-------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-------------+-------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | first_name | varchar(20) | NO | | NULL | | | middle_name | varchar(20) | YES | | NULL | | | last_name | varchar(20) | NO | | NULL | | | weight | int(11) | NO | | NULL | | +-------------+-------------+------+-----+---------+----------------+ 5 rows in set (0.00 sec) Please advise how to alter Flights to take the foreign key. TIA, Victor
