cannot add or update a child row

[nitinkhare1]

Please help,I'm very frustated.

when I ADD
the data in kn_history_ques tion table of htbase_tst database....it giving the error "Cannot add or update a child row:a foreign key constraint fails,<'htbase_ tst/kn_history_ques tion', CONSTRAINT 'FK_kn_history_ question_compla int' FOREIGN KEY ('complaint_id' ) REFERENCES 'complaint'('id ')).

This is my table script.....

CREATE TABLE `city` (
`id` int(11) NOT NULL auto_increment,
`city_name` varchar(255) default NULL,
`city_code` varchar(80) default NULL,
`state_id` int(11) default NULL,
`Nearest_airpor t_code` varchar(80) default NULL,
`date_updated` timestamp NULL default NULL,
`date_created` timestamp NULL default NULL,
PRIMARY KEY (`id`),
KEY `FK_cities_stat es` (`state_id`)
) ENGINE=MyISAM AUTO_INCREMENT= 11 DEFAULT CHARSET=utf8;


CREATE TABLE `kn_history_que stion` (
`id` int(11) NOT NULL auto_increment,
`complaint_id` int(11) default NULL,
`question_text` varchar(255) default NULL,
`sex_relevance` varchar(20) default NULL,
`age_group_rele vance` varchar(255) default NULL,
`date_created` timestamp NOT NULL default CURRENT_TIMESTA MP on update CURRENT_TIMESTA MP,
`date_updated` timestamp NOT NULL default '0000-00-00 00:00:00',
`count_of_respo nses` int(5) default NULL COMMENT ', paint radio buttons if value is one else check boxes',
`doctor_id` int(11) default NULL,
PRIMARY KEY (`id`),
KEY `FK_kn_history_ question_compla int` (`complaint_id` ),
CONSTRAINT `FK_kn_history_ question_compla int` FOREIGN KEY (`complaint_id` ) REFERENCES `complaint` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


ERROR:"Cannot add or update a child row:a foreign key constraint fails,<'htbase_ tst/kn_history_ques tion', CONSTRAINT 'FK_kn_history_ question_compla int' FOREIGN KEY ('complaint_id' ) REFERENCES 'complaint'('id ')).

Please give the solution of this ERROR.

[dafodil]

Some row in the child does not comply with the constraint, correct the problem.
You find the rows like this:
select child.id from child left join parent on (child.parent_i d=parent.id) where child.id is not null and parent.id is null;