1. A method executed by a procurement catalog server and an enterprise procurement application coupled to one or more clients and one or more external sites over a network connection, the method comprising: determining a classification of items in an order procurement catalog retrieved from a procurement catalog database, the order procurement catalog allowing a user to order an item, the classification organizing a plurality of types of items in the classification amongst categories; arranging the categories as a plurality of nodes in a category hierarchy; tracing a path along the category hierarchy to determine an ancestral relationship between the plurality of nodes; analyzing a tracing direction of the path to identify adjacent nodes at a same level in the hierarchy; receiving, from the client over the network connection, a query for an item using the enterprise procurement application for the order procurement catalog, the enterprise procurement application configured to allow a user in an enterprise to order items from the order procurement catalog over the network using the client; determining a plurality of items for the query based upon the category in which the item is included, with said category including related items associated with nodes adjacent to the node to which the item is associated, wherein the plurality of items includes a first type of item and a second type of item, wherein the first type of item requires a different method of ordering from the second type of item; and displaying the plurality of items, including the related items, in response to the query for procurement by the user thereof.