Consider the following database table design:
CREATE TABLE `notifications` (
`id` INT NOT NULL AUTO_INCREMENT,
`type` INT(8) NOT NULL,
`notifiable_id` INT unsigned NOT NULL,
`notifiable_type` VARCHAR(10) NOT NULL,
`relation_id_1` INT unsigned,
`relation_type_1` VARCHAR(10),
`relation_id_2` INT unsigned,
`relation_type_2` VARCHAR(10),
`updated_at` TIMESTAMP NOT NULL,
`created_at` TIMESTAMP NOT NULL,
PRIMARY KEY (`id`)
);
What is wrong with the above and how could it be improved?
