SQLSTATE [23000]：违反完整性约束：1452无法添加或更新子行：外键约束失败

Question

I am using cakePHP framework in my web project,It seems many people have already ask similar question before.Even I try for those I couldn't find the answer.

Here is the error I got'

Database Error

Error: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`fit_or_fat`.`disease_suggestions`, CONSTRAINT `disease_suggestions_ibfk_1` FOREIGN KEY (`disease_id`) REFERENCES `diseases` (`id`) ON DELETE CASCADE ON UPDATE CASCADE)

SQL Query: INSERT INTO `fit_or_fat`.`disease_suggestions` (`title`, `suggestion`, `disease_id`, `modified`, `created`) VALUES ('cholestorol', 'dddddddddddddddd', 'dd', '2014-08-24 00:04:32', '2014-08-24 00:04:32') 

This is my model

'disease_id' => array(
            'notEmpty' => array(
                'rule' => array('notEmpty'),
                'message' => 'disease_id must not be empty',
            ),
            'custom' => array(
                'rule' => '/[\w\s\d., \-_]+/',
                'message' => 'user_id can only contain simple and capital letters, 0-9 numbers, . , - _ space and tabs only.',
            ),
        ),

Answer 1

You appear to be adding dd to the disease_id column. Which has a constraint. Most often ID columns are numerical. So this warning is telling you the the query is wrong, or specifically trying to insert values not allowed.

INSERT INTO `fit_or_fat`.`disease_suggestions` (`title`, `suggestion`, `disease_id`, `modified`, `created`) VALUES ('cholestorol', 'dddddddddddddddd', 1, '2014-08-24 00:04:32', '2014-08-24 00:04:32') 

Will most likely be allowed (I have no idea what disease is on ID 1 but that's another issue all together).