Logical integration of locally independent relational databases into a distributed database

This paper discusses a constraint integration problem, which occurs in constructing a global view of a distributed database by local relational databases. Each local database has its own semantic constraints. such as functional, join and embedded join dependencies (FDs. JDs and EJDs, respectively). A global view of a distributed database is assumed to be defined by taking a join of these local databases. Some dependency constraints on a local database may be violated on a global view. In this paper, we show (a) the relationship between dependencies of local databases and dependencies appearing in a global view, (b) a testing method whether an EJD appears in a global view when only FDs and JDs are given to each local database, end (c) some conditions for a JD of a local database to appear in a global view as an EJD.