On Wed, Mar 3, 2010 at 7:38 AM, Louis-David Mitterrand <vindex+lists-pgsql-...@apartia.org> wrote:
> Each ship is different and has specific cabin types and categories. Of > course there is some overlap between ships but I thought it simpler (or > more elegant) to use that hierarchy. Maybe my schema is wrong? I'm probably ignorant about ships, but are ships like air planes in that all ships belong to a similar class/construction? i.e. all Bowing 747 are essentially configured that same. Can you define ship classes that each ship belongs? You describe cabin_category as if it is actually an area of this ship, would all ships of a class have nearly identical ship_areas/cabin_categories? > I could add an id_ship to 'cabin' but that would make two (potentialy > conflicting) relations to 'ship'. It true that more refinement is necessary. As you've mentioned that this hierarchy will have overlap, this is an indication of a violation of the second normal form (I believe). -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
