[thelist] Newbie - DB Design Help
Ken Schaefer
Ken at adOpenStatic.com
Sat Jul 29 05:47:37 CDT 2006
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.
More information about the thelist
mailing list