Question

I’m trying to create a single table for private messaging on a website. I created the following table which I think is efficient but I would really appreciate some feedback.

CREATE TABLE IF NOT EXISTS `pm` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `to` int(11) NOT NULL,
  `date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `subject` varchar(255) DEFAULT NULL,
  `message` text NOT NULL,
  `read` tinyint(1) NOT NULL DEFAULT '0',
  `deleted` tinyint(1) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
  FOREIGN KEY (user_id) REFERENCES User(user_id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

I have 2 columns that determine the status of the message: read and deleted

If read = 1, the message has been read by the receiver. If deleted = 1, either the sender or the receiver deleted the message from the sent or received inbox. If deleted = 2 both users deleted the message, therefor delete the row from the database table.

Answer 1

A few comments:

Charset=latin1 is going to piss some people of I’d suggest charset=utf8.

I’d suggest putting a foreign key check in not only on user_id, but on to as well.

Also I’d put an index on date, as you will be doing a lot of sorting on that field.

You need to split deleted in two fields, otherwise you will not know which user has deleted the message. (deleted_by_user, deleted_by_recipient)

Note that date is a reserved word and you’ll need to change it into message_date or `backtick` it in your queries.