title: Cannot delete or update a parent row: a foreign key constraint fails
body: <p>When doing:</p>
  
  <pre><code>DELETE FROM `jobs` WHERE `job_id` =1 LIMIT 1 
  </code></pre>
  
  <p>It errors:</p>
  
  <pre><code>#1451 - Cannot delete or update a parent row: a foreign key constraint fails 
  (paymesomething.advertisers, CONSTRAINT advertisers_ibfk_1 FOREIGN KEY 
  (advertiser_id) REFERENCES jobs (advertiser_id))
  </code></pre>
  
  <p>Here are my tables:</p>
  
  <pre><code>CREATE TABLE IF NOT EXISTS `advertisers` (
    `advertiser_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
    `name` varchar(255) NOT NULL,
    `password` char(32) NOT NULL,
    `email` varchar(128) NOT NULL,
    `address` varchar(255) NOT NULL,
    `phone` varchar(255) NOT NULL,
    `fax` varchar(255) NOT NULL,
    `session_token` char(30) NOT NULL,
    PRIMARY KEY (`advertiser_id`),
    UNIQUE KEY `email` (`email`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
  
  
  INSERT INTO `advertisers` (`advertiser_id`, `name`, `password`, `email`, `address`, `phone`, `fax`, `session_token`) VALUES
  (1, 'TEST COMPANY', '', '', '', '', '', '');
  
  CREATE TABLE IF NOT EXISTS `jobs` (
    `job_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
    `advertiser_id` int(11) unsigned NOT NULL,
    `name` varchar(255) NOT NULL,
    `shortdesc` varchar(255) NOT NULL,
    `longdesc` text NOT NULL,
    `address` varchar(255) NOT NULL,
    `time_added` int(11) NOT NULL,
    `active` tinyint(1) NOT NULL,
    `moderated` tinyint(1) NOT NULL,
    PRIMARY KEY (`job_id`),
    KEY `advertiser_id` (`advertiser_id`,`active`,`moderated`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
  
  
  INSERT INTO `jobs` (`job_id`, `advertiser_id`, `name`, `shortdesc`, `longdesc`, `address`, `active`, `moderated`) VALUES
  (1, 1, 'TEST', 'TESTTEST', 'TESTTESTES', '', 0, 0);
  
  ALTER TABLE `advertisers`
    ADD CONSTRAINT `advertisers_ibfk_1` FOREIGN KEY (`advertiser_id`) REFERENCES `jobs` (`advertiser_id`);
  </code></pre>