Question

I’m doing the Agile Yii book.

Anyway, I’m trying to execute this command:

INSERT INTO tbl_project_user_assignment (project_id, user_id) values ('1','1'), ('1','2');

And I get this error:

ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`trackstar_dev`.`tbl_project_user_assignment`, CONSTRAINT `FK_project_user` FOREIGN KEY (`project_id`) REFERENCES `tbl_project` (`id`) ON DELETE CASCADE)

So.. I figure let’s see if tbl_project table have project_id=1. Did a quick SELECT * FROM tbl_project; and the project exist.

Ok then let’s just check the user, SELECT * FROM tbl_user; Yup 2 user with id 1 and 2.

What am I doing wrong? Is there a typo? The agile yii book have several typos but they’re not as serious and it’s too new so there’s no errata reported (checked already).

Here’s the database schema from the source code:

-- Disable foreign keys
SET FOREIGN_KEY_CHECKS = 0 ;

-- Create tables section -------------------------------------------------

-- Table tbl_project

CREATE TABLE IF NOT EXISTS `tbl_project` (
  `id` INTEGER NOT NULL auto_increment,
  `name` varchar(128) NOT NULL,
  `description` text NOT NULL,
  `create_time` DATETIME default NULL,
  `create_user_id` INTEGER default NULL,
  `update_time` DATETIME default NULL,
  `update_user_id` INTEGER default NULL,
  PRIMARY KEY  (`id`)
) ENGINE = InnoDB
;

-- DROP TABLE IF EXISTS `tbl_issue` ;

CREATE TABLE IF NOT EXISTS `tbl_issue` 
( 
  `id` INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  `name` varchar(256) NOT NULL,
  `description` varchar(2000), 
  `project_id` INTEGER,
  `type_id` INTEGER,
  `status_id` INTEGER,
  `owner_id` INTEGER,
  `requester_id` INTEGER,
  `create_time` DATETIME,
  `create_user_id` INTEGER,
  `update_time` DATETIME,
  `update_user_id` INTEGER  
) ENGINE = InnoDB
; 

-- DROP TABLE IF EXISTS `tbl_user` ;

-- Table User

CREATE TABLE IF NOT EXISTS `tbl_user` 
(
  `id` INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  `email` Varchar(256) NOT NULL,
  `username` Varchar(256),
  `password` Varchar(256),
  `last_login_time` Datetime,
  `create_time` DATETIME,
  `create_user_id` INTEGER,
  `update_time` DATETIME,
  `update_user_id` INTEGER
) ENGINE = InnoDB
; 

-- DROP TABLE IF EXISTS `tbl_project_user_assignment` ;

-- Table User

CREATE TABLE IF NOT EXISTS `tbl_project_user_assignment`
(
  `project_id` Int(11) NOT NULL,
  `user_id` Int(11) NOT NULL,
  `create_time` DATETIME,
  `create_user_id` INTEGER,
  `update_time` DATETIME,
  `update_user_id` INTEGER,
 PRIMARY KEY (`project_id`,`user_id`)
) ENGINE = InnoDB
;


-- The Relationships 
ALTER TABLE `tbl_issue` ADD CONSTRAINT `FK_issue_project` FOREIGN KEY (`project_id`) REFERENCES `tbl_project` (`id`) ON DELETE CASCADE ON UPDATE RESTRICT;

ALTER TABLE `tbl_issue` ADD CONSTRAINT `FK_issue_owner` FOREIGN KEY (`owner_id`) REFERENCES `tbl_user` (`id`) ON DELETE CASCADE ON UPDATE RESTRICT; 

ALTER TABLE `tbl_issue` ADD CONSTRAINT `FK_issue_requester` FOREIGN KEY (`requester_id`) REFERENCES `tbl_user` (`id`) ON DELETE CASCADE ON UPDATE RESTRICT; 

ALTER TABLE `tbl_project_user_assignment` ADD CONSTRAINT `FK_project_user` FOREIGN KEY (`project_id`) REFERENCES `tbl_project` (`id`) ON DELETE CASCADE ON UPDATE RESTRICT;

ALTER TABLE `tbl_project_user_assignment` ADD CONSTRAINT `FK_user_project` FOREIGN KEY (`user_id`) REFERENCES `tbl_user` (`id`) ON DELETE CASCADE ON UPDATE RESTRICT;   

-- Insert some seed data so we can just begin using the database
INSERT INTO `tbl_user` 
  (`email`, `username`, `password`) 
VALUES 
  ('[e-mail]','Test_User_One', MD5('test1')),
  ('[e-mail]','Test_User_Two', MD5('test2'))    
;

-- Enable foreign keys
SET FOREIGN_KEY_CHECKS = 1 ;

Anyway, thanks in advance!

EDIT:
Clarification that the project does indeed exist ^^.

mysql> select id,name from tbl_project;

+—-+——————-+

| id | name |

+—-+——————-+

| 6 | Project 1 |

| 1 | project zombied 1 |

+—-+——————-+

2 rows in set (0.00 sec)

Answer 1

The project_id and user_id in tbl_project_user_assignment are typed as INT(11) rather than INTEGER. I’m inclined to think that INTEGER is 4 BYTES and INT(11) would go to 8 BYTES.

As commented above INTEGER fixes the problem.