Celko Nested Sets Vs. Linked Tables

Hi,

I am trying to revamp our product database with a view to making it search-optmised and would like some guidance (or confirmation of method, if you will!!). We currently use a three table structure (Product, Brand, Cat(egory)) along the lines of :

create table product
(prod_id int not null,
brand_id int not null,
cat_id int not null,
other stuff e.g. tech. specs, displayed text on web page, etc....
)

with corresponding brand_id and cat_id in the other tables. While this seems relationally sound I see it as being inefficient for searching, particularly after reading the theory behind nested sets.

A new function I am building will enable users to drill down through the product list or runs searches against all or part of the db :

e.g. all products from one category,
all products fitting certain search criteria,
products from several selected brands fitting certain criteria,
and any combination of the above you can think of!

The problem is, not all products have the same criteria list (in fact I would be surprised if any did) and may also be of more than one category (a digital camera with movie mode might easily fit into the digital camcorder search). I think I am correct in that a nested set would make the structure fit the requirement - things like criteria, displayable text, etc. could be nodes in their own right and each logical level might have its own criteria. For example, if a category is selected then certain text must be displayed and could list further categories or products. The next level down would then require its own displayable text - I am mainly thinking about SEO tags here. Also, I am not precious about retaining the current table structure and would like an open ended solution where I can add further data/functionality in a dynamic fashion, which nested sets seem to embody.

Does this make sense to anybody coz I think I've confused myself even more!!

Thanks in advance,

G