Re: database model tshirt sizes

another approach would be:

table product:
> productid int8 PK
> productname charvar(255)

table versions
> productid int8 FK
> versionid int8 PK
> size
> color
> ...
> quantity int4

an example would be then:

table product:
- productid: 123, productname: 'nice cotton t-shirt'
- productid: 442, productname: 'another cotton t-shirt'

table versions:
- productid: 123, versionid: 1, color: 'black', size: 'all', quantity: 11
- productid: 442, versionid: 2, color: 'yellow', size: 'l', quantity: 1
- productid: 442, versionid: 2, color: 'yellow', size: 's', quantity: 4
- productid: 442, versionid: 2, color: 'red', size: 'xl', quantity: 9
- productid: 442, versionid: 2, color: 'blue', size: 's', quantity: 0

that way you can have more than 1 quantity / color / size combination per
product and still have products that come in one size. so instead of only
using a 2nd table for cases where more than one size is available, you would
always use a 2nd table. this probably reduces your code complexity quite a
bit and only needs 1 JOIN.

- thomas

----- Original Message -----
From: "Patrick Hatcher" <PHatcher(at)macys(dot)com>
To: "NbForYou" <nbforyou(at)hotmail(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>;
<pgsql-performance-owner(at)postgresql(dot)org>
Sent: Sunday, March 19, 2006 2:59 PM
Subject: Re: [PERFORM] database model tshirt sizes

> We have size and color in the product table itself. It is really an
> attribute of the product. If you update the availability of the product
> often, I would split out the quantity into a separate table so that you
> can
> truncate and update as needed.
>
> Patrick Hatcher
> Development Manager Analytics/MIO
> Macys.com
>
>
>
> "NbForYou"
> <nbforyou(at)hotmail
> .com> To
> Sent by: <pgsql-performance(at)postgresql(dot)org>
> pgsql-performance cc
> -owner(at)postgresql
> .org Subject
> [PERFORM] database model tshirt
> sizes
> 03/18/06 07:03 AM
>
>
>
>
>
>
>
>
>
> Hello,
>
> Does anybody know how to build a database model to include sizes for
> rings,
> tshirts, etc?
>
>
> the current database is built like:
>
> table product
> =========
>
> productid int8 PK
> productname charvar(255)
> quantity int4
>
>
> what i want now is that WHEN (not all products have multiple sizes) there
> are multiple sizes available. The sizes are stored into the database. I
> was
> wondering to include a extra table:
>
> table sizes:
> ========
> productid int8 FK
> size varchar(100)
>
>
> but then i have a quantity problem. Because now not all size quantities
> can
> be stored into this table, because it allready exist in my product table.
>
> How do professionals do it? How do they make their model to include sizes
> if any available?
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match
>