your advice on tables

At the moment i have three tables with the following columns:

Supplier table:
Vendor number (primary key)
Name
Address 1
Address 2
Town
Postcode
Phone
Fax
Group
Description

Iso Table
Vendor number
Name
iso 1
iso2
iso3
iso4
reach

Comments table
Vendor number
name
vendor non conformities
comments

Is this a good layout or can you reckon mend a better table layout

Can you explain better the last two tables?

why iso1, iso2, iso3?
why do all tables have a name field? and a Vendor number?

"Savage" wrote:

At the moment i have three tables with the following columns:

Supplier table:
Vendor number (primary key)
Name
Address 1
Address 2
Town
Postcode
Phone
Fax
Group
Description

Iso Table
Vendor number
Name
iso 1
iso2
iso3
iso4
reach

Comments table
Vendor number
name
vendor non conformities
comments

Is this a good layout or can you reckon mend a better table layout

On Wed, 24 Sep 2008 03:54:00 -0700, Rui
wrote:

Can you explain better the last two tables?

why iso1, iso2, iso3?
why do all tables have a name field? and a Vendor number?

"Savage" wrote:

At the moment i have three tables with the following columns:

Supplier table:
Vendor number (primary key)
Name
Address 1
Address 2
Town
Postcode
Phone
Fax
Group
Description

Iso Table
Vendor number
Name
iso 1
iso2
iso3
iso4
reach

Comments table
Vendor number
name
vendor non conformities
comments

Is this a good layout or can you reckon mend a better table layout


Yes, usually seeing numbered fields (iso1, iso2, etc.) means that the
structure isn't normalized. It's harder to query later, and you're
out of luck when iso5 comes along.

Also:

- You have a "Name" field in each table after Vendor Number. I hope
that isn't Vendor Name, since that would be retrievable by joining to
the vendor table.

- Is the Group a lookup to another Group table?

- Don't your Comments need a date for each one? How about the person
making the comment?

- How many non-conformities can be in each Comment? Plural fields are
usually a sign of trouble too.

Have you read Database Design for Mere Mortals (Hernandez)? It's a
great way to learn about database design principles.

Hope this helps,

Armen Stein
Microsoft Access MVP
www.JStreetTech.com