Re: relational databases
Date: 13 Feb 2003 06:31:49 -0800
Message-ID: <f12b00a0.0302130631.3ed7e545_at_posting.google.com>
Alan Gutierrez <ajglist_at_izzy.net> wrote in message news:<Pine.WNT.4.53.0302120843510.1332_at_CX1198465-B>...
> On Wed, 12 Feb 2003, wombat wrote:
>
> > I have a database assignment that seems to product a relation with one
> > composite primary key and no other attributes. It does not link two
> > relations, but just extends off of one. Is this legal? The relation
> > contains three attributes; ProductID, ProductName and ProductType.
> > The ProductType contains repeating groups and is not sustained by the
> > primary key (productid), so has been removed along with a copy of the
> > primary key to a new relation, but this creates a table with only a
> > primary key and no other relations. It does solve the problem of some
> > redundancy, but not much. Is this correct?
>
> Some redundancy? Just a little is annoying. Could you please post the
> DDL for the tables in question. It would make it much easier to
> visualize you problem.
>
> Alan Gutierrez - ajglist_at_izzy.net
In our assigment we have been given a snippet of sample data and told to normalise it to BCNF. The sample data is as follows:
ProductID ProdName ProdType PartNo PartCost AsNo AsName ToolID
101 Sink Bthroom 123 25.78 4342 Olive AB53 101 Sink Bthroom 156 26.45 6543 Brown ER34 105 Bath Bthroom 156 26.45 2321 Green TR34 105 Bath Bthroom 178 101.23 6543 Brown PO23 108 Stool General 123 25.78 8767 Smith QW12 108 Stool General 164 32.00 OI98 Brown YT45
Obviously, to get rid of further redundancy I have to finish the normalisation process.
As I am fairly new to this concept, I wasn't sure what you meant by DDL so I hope this explains it to you more clearly. Thanks for your help.
Wombat Received on Thu Feb 13 2003 - 15:31:49 CET