In a network system including a server apparatus, client apparatus, and
database, when a registration request of catalog data of a catalog is
received from the client apparatus, the catalog data is registered in the
database as one file of the catalog. When a registration request of
merchandise information to be associated with the catalog data is
received from the client apparatus, the merchandise information is
registered as one page of the catalog data. Hence, the merchandise
information of the catalog can be associated with catalog data of each
page.