A data transforming method is provided which can perform a transforming
process of transforming collective order data for a plurality of products
into individual order data for each individual product and a transforming
process in which order data is inherited to a response data transforming
process. For each combination of transform source and destination
protocols, various designation information is stored beforehand in a
mapping definition information area and transaction data is transferred
in accordance with the designation information. Designation information
includes information of a request for an individual order data division
process and a collective response data collection process and information
of a correspondence between data items of transaction data.