Platforms? I assume SQL 2005 or 8.
What types of products are we talking about... single level bills? Tiered?
Is this just a management tool or is there a need to tie it into a order processing platform?
Do you want the interface to be web driven, client based?
Or business here is a tier bill of materials for residential and commercial windows.. we use a configuration driven Q&A with the options tied to multiple choice questions.. stock verse custom. Each question will drive the bill for the related choice.
From the engineering standpoint, all parts are maintained in tables, pulled with scripting logic. But a simple query can pull back all parts and where they are used in the configurations based on product type and option.
All parts are kept in a single item master table with all purchase, stocking and costing information.
"The oranges are dry; the apples are mealy; and the papayas... I don't know what's going on with the papayas!"