You can always add categories later if you come across an unhandled category. For the question of an accident being in more than one category, you can introduce a table to map accidents to a category resulting in 3 tables 1. Accident - contains the accident details, time, location... Blah blah blah 2. Categories - contains ur accidents defination 3. AccidentMappings - maps an accident to a catrgory, contains 2 foreign keys categoryID, AccidentID . Add a unique key on (categoryID,AccidentID) Sent from my BlackBerry® -----Original Message----- From: Peter Karunyu <pkarunyu@gmail.com> Sender: skunkworks-bounces@lists.my.co.ke Date: Tue, 25 Oct 2011 11:40:02 To: Shadrack Mwaniki<shadrack_mwaniki@yahoo.com>; Skunkworks Mailing List<skunkworks@lists.my.co.ke> Reply-To: Skunkworks Mailing List <skunkworks@lists.my.co.ke> Subject: Re: [Skunkworks] Database design question _______________________________________________ Skunkworks mailing list Skunkworks@lists.my.co.ke http://orion.my.co.ke/cgi-bin/mailman/listinfo/skunkworks ------------ Skunkworks Rules http://my.co.ke/phpbb/viewtopic.php?f=24&t=94 ------------ Other services @ http://my.co.ke