Creating Efficient Schemas for Dependency Lookups

	I have been tasked to create a DB that tracks all
	inter and intra dependencies of software my project
	uses.  There is approx.	65 titles from about 40 vendors.  
	As all those product versions evolve,  the need to 
	maintain sanity	is crucial. Thus, the database.  

	Version "X" of product "Y"  depends on or is not 
	compatible with version "A" of product "B". is the
	classic information to smoothly maintain.  It can all 
	turn into a plate of spaghetti pretty quickly.

	Does anyone have suggestions and / or examples
	of efficient schema designs and algorithms to
	efficiently create a system that tracks many
	and multi level dependencies of items ?


	Many thanks in advance.
	Terry    terry.hampton_at_convergys.com