title: Integrity constraint violation: 1452 Cannot add or update a child row:
body: <p>I am trying to insert values into my comments table and I am getting a error. Its saying that I can not add or update child row and I have no idea what that means.</p>
  
  <p>my schema looks something like this</p>
  
  <pre><code>-- ----------------------------
  -- Table structure for `comments`
  -- ----------------------------
  DROP TABLE IF EXISTS `comments`;
  CREATE TABLE `comments` (
    `id` varchar(36) NOT NULL,
    `project_id` varchar(36) NOT NULL,
    `user_id` varchar(36) NOT NULL,
    `task_id` varchar(36) NOT NULL,
    `data_type_id` varchar(36) NOT NULL,
    `data_path` varchar(255) DEFAULT NULL,
    `message` longtext,
    `created` datetime DEFAULT NULL,
    `modified` datetime DEFAULT NULL,
    PRIMARY KEY (`id`),
    KEY `fk_comments_users` (`user_id`),
    KEY `fk_comments_projects1` (`project_id`),
    KEY `fk_comments_data_types1` (`data_type_id`),
    CONSTRAINT `fk_comments_data_types1` FOREIGN KEY (`data_type_id`) REFERENCES `data_types` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT `fk_comments_projects1` FOREIGN KEY (`project_id`) REFERENCES `projects` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
    CONSTRAINT `fk_comments_users` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
  ) ENGINE=InnoDB DEFAULT CHARSET=utf32;
  
  -- ----------------------------
  -- Records of comments
  -- ----------------------------
  
  -- ----------------------------
  -- Table structure for `projects`
  -- ----------------------------
  DROP TABLE IF EXISTS `projects`;
  CREATE TABLE `projects` (
    `id` varchar(36) NOT NULL,
    `user_id` varchar(36) NOT NULL,
    `title` varchar(45) DEFAULT NULL,
    `description` longtext,
    `created` datetime DEFAULT NULL,
    `modified` datetime DEFAULT NULL,
    PRIMARY KEY (`id`),
    KEY `fk_projects_users1` (`user_id`),
    CONSTRAINT `fk_projects_users1` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
  ) ENGINE=InnoDB DEFAULT CHARSET=utf32;
  
  -- ----------------------------
  -- Records of projects
  -- ----------------------------
  INSERT INTO `projects` VALUES ('50dcbc72-3410-4596-8b71-0e80ae7aaee3', '50dcbc5c-d684-40bf-9715-0becae7aaee3', 'Brand New Project', 'This is a brand new project', '2012-12-27 15:24:02', '2012-12-27 15:24:02');
  </code></pre>
  
  <p>and the mysql statement I am trying to do looks something like this</p>
  
  <pre><code>INSERT INTO `anthonyl_fbpj`.`comments` (`project_id`, `user_id`, `task_id`, `data_type_id`, `message`, `modified`, `created`, `id`) 
  VALUES ('50dc845a-83e4-4db3-8705-5432ae7aaee3', '50dcbc5c-d684-40bf-9715-0becae7aaee3', '1', '50d32e5c-abdc-491a-a0ef-25d84e9f49a8', 'this is a test', '2012-12-27 19:20:46', '2012-12-27 19:20:46', '50dcf3ee-8bf4-4685-aa45-4eb4ae7aaee3')
  </code></pre>
  
  <p>the error I get looks like this</p>
  
  <blockquote>
    <p>SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or
    update a child row: a foreign key constraint fails
    (<code>anthonyl_fbpj</code>.<code>comments</code>, CONSTRAINT <code>fk_comments_projects1</code>
    FOREIGN KEY (<code>project_id</code>) REFERENCES <code>projects</code> (<code>id</code>) ON DELETE NO
    ACTION ON UPDATE NO ACTION)</p>
  </blockquote>