database and web site needed

My project has 2 elements: - The database that connects several different catalogs into a common intermediate format, and - The web site that users can select items from and then it queries the catalogs and displays the items that were returned. The display would be a simple multi-column format, so if the same item(s) are listed in several catalogs, they would display across from each other so the user can visually compare them. I have an extremely rough version laid out in MS Access, but I am far from understanding all that is needed to actually make this work.