Question

I have inherited a PHP project and the client is wanting to add some functionality to their CMS, basically the CMS allows them to create some news, all the news starts with the same content, and that is saved in one table, the actually news headline and articles are saved in another table, and the images for the news are saved in another, basically if the base row for the news is deleted I need all the related rows to be deleted, the database is not setup to work with foreign keys so I cannot use cascade deletion, so how can I delete the all the content I need to, when I only what the ID of the base news row is?

Any help would be very helpful I am sorry I cannot give you much more help, here is this the original SQL of tables scheme if that helps?

    --
-- Table structure for table `mailers`
--

CREATE TABLE IF NOT EXISTS `mailers` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `mailer_title` varchar(150) NOT NULL,
  `mailer_header` varchar(60) NOT NULL,
  `mailer_type` enum('single','multi') NOT NULL,
  `introduction` varchar(80) NOT NULL,
  `status` enum('live','dead','draft') NOT NULL,
  `flag` enum('sent','unsent') NOT NULL,
  `date_mailer_created` int(11) NOT NULL,
  `date_mailer_updated` int(10) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=13 ;

-- --------------------------------------------------------

--
-- Table structure for table `mailer_content`
--

CREATE TABLE IF NOT EXISTS `mailer_content` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `headline` varchar(60) NOT NULL,
  `content` text NOT NULL,
  `mailer_id` int(11) NOT NULL,
  `position` enum('left','right','centre') DEFAULT NULL,
  `created_at` int(10) NOT NULL,
  `updated_at` int(10) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=18 ;

-- --------------------------------------------------------

--
-- Table structure for table `mailer_images`
--

CREATE TABLE IF NOT EXISTS `mailer_images` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(150) NOT NULL,
  `filename` varchar(150) NOT NULL,
  `mailer_id` int(11) NOT NULL,
  `content_id` int(11) DEFAULT NULL,
  `date_created` int(10) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=15 ;

It is worth noting that the schema cannot be changed nor can I change to the DB to MYISAM so that I can use foreign keys.

Answer 1

Add foreign key to table mailer_content

FOREIGN KEY (mailer_id)
REFERENCES mailers(id)
ON DELETE CASCADE

Add foreign key to table mailer_images

FOREIGN KEY (content_id)
REFERENCES mailer_content(id)
ON DELETE CASCADE

http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html