Formal Model for Integration of Data in Complex Structure

In Internet, various kinds of data in variety of forms are stored. After obtaining data from distributed sites, we have to integrate them. One of the serious problem is how to integrate data in di erent structures. In this paper we will develop a form model for such a purpose. Since data structure is designed in order to reduce the complexities of the result, the structure re ects semantic constraints. For integration, a basic approach consists of the following steps. (1) Extract semantic constraints from data from every source. (2) Calculate semantic constraints common in all the structures. (3) Design data structure for the constraints obtained above. Since the structure itself is an expression of semantic constraints, we will discuss how to manipulate structures without converting them into intermediate semantic constraints. If each data item has one classi cation code, we have a functional dependency (frequently appearing semantic constraints) from the set of items to the set of classi cation code. We will use functional dependencies for structure conversion.