SQL Categories within Categories with Categories etc

Hi reiss20

You've made a reasonable start. Why would you need a parent and child category field in your Products table? To my mind a product should only need to know about the category immediately above it that it falls into. That category needs to know only its immediate parent and so on. You can make the category table self-referencing so that you can have as many levels as you like.  A top level category is simply one that has no parent.

So I would recommend that you have tables like this:

tblCategories:
>CatID
>ParentCatID
>CategoryName

tblProducts:
>ProductID
>CatID
>ProductName

A typical category chain might look like:

Category:
CatID: 1 ParentCatID: <null> CategoryName: Sports
CatID: 2 ParentCatID: 1 CategoryName: Baseball

Product:
ID: 1  CatID: 2 ProductName: Bat

Just one thing to be careful of; If you have an unlimited number of levels for your categories it can lead to some quite scary queries. You may be better off deciding on a fixed number of category levels and then having a separate table for each level. It's less flexible but it will make things simpler.

Regards
  Kelvin

Thanks for your help so far, much appreciated.

I've modified my table design to reflect your advice and i can now query the db to retrieve the product and its category. But as with my previous table design i can't figure out how to return all categories with  sub categories and products, can't seem to get my head around it e.g.

Category Sports:
        Inner Category Football:
                Product Football Boots
                Product Goal Posts
                Inner Inner Category Footballs:
                        Product Size 4 Ball
                        Product Size 5 Ball
        Inner Category Basketball:
                Product Spike Air Trainers
                Inner Inner Category Basketballs:
                        Product Outdoor ball
                        Product Indoor Ball
Category Movies:
        Inner Category Films beginning with R:
                Product Rambo 1
                Product Rambo 2
                Product Rambo 3
etc....


Can this be done witha query or will i have to use some logic in my server side code?

Thanks again

Hi KelvinY,

Thanks again for the advice. Decided just to have 3 category levels to keep things simple.

Sorry for the delay in getting back to you, was away on business.

Cheers,

Reiss