1. A method of constructing a database of organization activity, where a real model of the organization activity is a collection of actions of persons and organizations, said method comprising: defining an item by relating a plurality of other items handled in the organization activity with specified concepts forming the organization activity as an element to be subtracted, and the element to be subtracted; defining a sentence pattern by relating the specified concepts with a term prescribing action accompanying the organization activity and examples which can be taken by the term; creating a logical model corresponding to the real model by fitting the item to the sentence pattern; and creating a mounted model by converting the logical model into a descriptive system.