The present invention provides a method and apparatus for managing updates to a catalog based on a reference electronic catalog. The reference catalog has a reference format and a plurality of items, each with associated characteristics and the second catalog has a second format and a plurality of items, each with associated characteristics. The reference catalog is maintained with updates and revisions to the items and associated characteristics and the second catalog is maintained by repeating the mapping of at least a portion of the reference catalog into the second catalog after maintaining the reference catalog. Preferably, the maintenance times for both catalogs are recorded and the second catalog is maintained by comparing the recorded times and mapping only portions of the reference catalog that have been maintained into the second catalog.