For a hackathon a few years back I attempted to make the InnoDB engine in MySQL employ temporal queries. In theory, any change to a row would be timestamped, and `UPDATE` and `DELETE` remapped to `INSERT`.<p>The query plan for a regular query would be modified so that all referenced rows would be restricted to the matching row with the most recent timestamp. A temporal query would be restricted to the row with the most recent timestamp that was less than or equal to the provided time.