1. A method for operating a computer system to determine trade qualification of an item, the item containing a plurality of subassemblies, each subassembly potentially containing a plurality of subassemblies or being a base entry, the method comprising: the computer system maintaining a database of item records, with one record for each subassembly, each item record containing fields for information about the subassembly, including information relating to trade qualification; the computer system maintaining a database or relationship records, with each relationship record indicating a parent-child relationship between subassemblies; the computer system determining from a user an item to be trade qualified; for the determined item, the computer system selecting each subassembly which is present in the item utilizing the relationship records; the computer system traversing the selected subassemblies and determining trade qualification information for each subassembly based on the subassembly's constituent subassemblies using the item records; the computer system storing the determined trade qualification information for each subassembly as the determination is completed; the computer system determining the trade qualification information for the item based on its direct constituent subassemblies; and the computer system storing the determined trade qualification information of the item.