The bid field appears to be completely redundant in the schema you have below. You could achieve the same by simply having a composite PK that consists of the dept_Id and product_Id fields, which would be truer to 3rd normal form Cheers Ken -- My IIS Blog: www.adOpenStatic.com/cs/blogs/ken Tech.Ed Sydney: learn all about IIS 7.0 - See you there! : -----Original Message----- : From: thelist-bounces at lists.evolt.org [mailto:thelist- : bounces at lists.evolt.org] On Behalf Of Rob Smith : Sent: Saturday, 29 July 2006 1:45 AM : To: thelist at lists.evolt.org : Subject: Re: [thelist] Newbie - DB Design Help : : <snip>Generally your entities will become tables. Where entities have a : M:N (Many:Many) relationship, you will need a "bridging" table. If you : do up your ER model first, your database schema (at least in 3rd normal : form) writes itself.</snip> : : Yup. I agree that you disagree with me. You actually answered my next : post about the best way to rethink this approach: : : Bridge_Dept_Prod : Deptarments --------------------- : ---------------- bid int 4 PK Products : dept_id int 4 PK => dept_id int 4 FK ------------------- : ... product_id int 4 FK <= product_id int 4 PK : ... : : Yes, the bad and the good news here is that you get to effectively : micromanage the relationships in order to have a many-to-many : relationship.