[OT?] Database design

This is a little off topic... I am using PHP though :) I am using PHP4 to interface with an InterBase 6.0 customer / order/ product database. I want to assign each product to a category (more than one category in many cases), but I want to be able to add new categories easily (without hardcoding them in PHP). Any suggestions/criticisms about this database design: Products Table: ProductID, ProductName, ... ProductCategory Table: rProductID references products(ProductID), rProductCatID references ListProductCat(ProductCatID); ListProductCat Table: ProductCatID, Description; I can't think of a better way to do it. This setup allows me to have more than one category for each product and I can add new categories by adding a new field to the ListProductCat table. I could change the rProductCatID field in the ProductCategory table to restrict the values to a list, but then I have to change the table structure when I want to add a new category. Any ideas? TIA. Daniel Ems Spatial Data Integrations Louisville, KY 502.568.2591