Question

I have written some SQL code to create five tables with several relations(foreign keys).

The first foreign key relation works fine, the tables are created without any errors, but when I try to create gasten_url_toegangscodes I get the following error:

#1005 - Can't create table 'dbname.gasten_url_toegangscodes' (errno: 150).

I’ve read the docs about foreign keys and I still can’t find the problem.. The most strange thing about this is that it works in the first three tables..

Can anyone help me please?

My full SQL code is:

CREATE TABLE IF NOT EXISTS `groepen` (
  `id` tinyint(3) NOT NULL AUTO_INCREMENT,
  `naam` varchar(50) NOT NULL DEFAULT '',
  `status` tinyint(1) NOT NULL DEFAULT '1',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB;

CREATE TABLE IF NOT EXISTS `gasten` (
  `id` int(5) NOT NULL AUTO_INCREMENT,
  `bedrijf` varchar(100) NOT NULL DEFAULT '',
  `uniek` varchar(64) NOT NULL,
  `groepid` tinyint(3) NOT NULL,
  PRIMARY KEY (`id`),
  FOREIGN KEY (groepid) REFERENCES `groepen` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

CREATE TABLE IF NOT EXISTS `passen` (
  `id` tinyint(3) NOT NULL AUTO_INCREMENT,
  `naam` varchar(30) NOT NULL DEFAULT '',
  `color` varchar(7) NOT NULL DEFAULT '#FFFFFF',
  `bekend` tinyint(1) NOT NULL DEFAULT '0',
  `welkom` tinyint(1) NOT NULL DEFAULT '0',
  `aantal` tinyint(1) NOT NULL DEFAULT '0',
  `nummer` int(11) NOT NULL DEFAULT '0',
  `begrens` tinyint(1) NOT NULL DEFAULT '0',
  `status` tinyint(1) NOT NULL DEFAULT '1',
  `priority` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `naam` (`naam`)
) ENGINE=InnoDB;

CREATE TABLE IF NOT EXISTS `gasten_url_toegangscodes` (
  `uniek` varchar(64) NOT NULL,
  `unieke_url_code` char(64) NOT NULL,
  `salt` char(16) NOT NULL,
  FOREIGN KEY (uniek) REFERENCES `gasten` (`uniek`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE IF NOT EXISTS `gasten_tickets` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `pas_id` tinyint(3) NOT NULL,
  `uniek` varchar(64) NOT NULL,
  `barcode` char(16) NOT NULL,
  `secret_key` char(32) NOT NULL,
  `download_count` int(11) NOT NULL DEFAULT '0',
  `last_download_time` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `scanned` enum('N','Y') NOT NULL,
  `scanned_datetime` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  PRIMARY KEY (`id`),
  FOREIGN KEY (uniek) REFERENCES `gasten` (`uniek`) ON DELETE CASCADE ON UPDATE NO ACTION,
  FOREIGN KEY (pas_id) REFERENCES `passen` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

Thanks in advance!

Answer 1

Create an index on gasten.uniek

CREATE TABLE IF NOT EXISTS `gasten` (
  `id` int(5) NOT NULL AUTO_INCREMENT,
  `bedrijf` varchar(100) NOT NULL DEFAULT '',
  `uniek` varchar(64) NOT NULL,
  `groepid` tinyint(3) NOT NULL,
  PRIMARY KEY (`id`),
  INDEX `idx_uniek` (`uniek`),
  FOREIGN KEY (groepid) REFERENCES `groepen` (`id`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB;

And set the charset of the FK in gasten_url_toegangscodes the same as that of the related column in gasten.

Assuming gasten is UTF-8:

CREATE TABLE IF NOT EXISTS `gasten_url_toegangscodes` (
  /* use same charset for this column */
  `uniek` varchar(64) NOT NULL CHARSET UTF-8,
  `unieke_url_code` char(64) NOT NULL,
  `salt` char(16) NOT NULL,
  FOREIGN KEY (uniek) REFERENCES `gasten` (`uniek`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1;