A method of totally managing a plurality of sets of construction-related information and a plurality of sets of production-related information, each of said plurality of sets of construction-related information relating a constructional relationship between a corresponding one of a plurality of products to be produced and a plurality of parts which constitute said each product, while said plurality of sets of production-related information relating production of said products, respectively, said method comprising the steps of:
- determining each of said plurality of sets of construction-related information and said plurality of sets of production-related information as a corresponding one of a plurality of subjects which can be similarly processed;
- extracting at least one relationship of each of said plurality of subjects with the other of said subjects;
- classifying said plurality of subjects into a plurality of classes on the basis of the extracted at least one relationship of said each subject;
- generating subject substance data indicative of a substance of said each subject and relationship substance data indicative of a substance of said at least one relationship of said each subject;
- storing, for said each subject, a set of subject data incorporating a plurality of sets of element data in relation to each other, in a product information memory, said plurality of element data including said subject substance data and said relationship substance data of said each subject;
- and
- retrieving said set of subject data for at least one of said plurality of subjects from said product information memory, and outputting the retrieved set of subject data.