Re: tracking shipments, inventory
Date: 27 Dec 2004 07:23:33 -0800
Message-ID: <1104161013.605067.148520_at_f14g2000cwb.googlegroups.com>
>> negative stock quantities are entirely
possible in this database design but impossible in the real world
(putting aside the issue of backorders). Sure I can add logic in procs
and triggers to prevent a negative stock situation.... but that's the
burdensome and worrisome part. WHAT IF there's a hole in that logic?
How do I make bombproof rules to enforce these sorts of temporal
constraints?
...<<
I'd create a table shipment_piece(shipment_pk not null, delivered_to_pk), one row per a piece. You'd use up some more space, but never ever get negative quantities in stock:
select count(*) from shipment_piece where delivered_to_pk is null
This query never returns negative numbers. And yes, if the pieces are not distinguishable, that refers to a well know 'cat food' problem. Received on Mon Dec 27 2004 - 16:23:33 CET