Hi John,

Having recently been through this same process, I'll share what I learned.

As I know, the major difference for the fashion style is, it consist of size and colour. I used to see some other software that use matrix as a tool for colour and size selection. Do you think it is the good ideas? IS it just use grid to display the colour and size on row and column basis, and detect which column is selection by user to determine the colour and size?
Also, I found that, I have to add colour and size fields into my item table. All of my reports have to be modified. Any way to minimize the modification?

This has been handled many ways by others - this is how I setup my tables:

Supplier -> Products -> Styles -> Sizing

with -> indicating the persistant relations between the tables. Products contains a product ID and a category ID - the first to link to Styles, the second for reporting purposes. Categories are simply 1 through 8, for Pants, Jackets, etc. Styles contains each unique product you sell by color, style, size. I used an integer PK, modified to generate a second character field that becomes a barcode. This table also contains a matrix field C(1) that links to the sizing table. As of this moment, the Sizing has 8 records by 18 fields, giving me all the combinations I need for reporting purposes. As an example, the first record I'll call "A" sizing. The fields will hold the sizes for an "A" sized product - XS,S,M,L,XL,2XL and so on. Maybe "B" sizing is for shoes, so those fields would be like 5.0,5.5,6.0 etc. I use this table just for reporting and purchase orders. And this is the limit of my 'matrix'.

Maybe not the best implementation, it works well for my client.