Research And Design On Multidatabase System

As communication technology and database technology developing rapidly,more and more application systems have to access many heterogeneous and distributed databases to achieve their tasks.Multidatabase system can provide a uniform and compositive multidatabase environment and make user access these databases by using a uniform schema and a simple query language without changing these databases.In this thesis,schema integration global query decomposition and optimization and global transactions manipulation in multidatabase systems are discoursed elaboratly.The algorithm which clears up one-to-one entity conflict and query process optimization algorithm are presented and analysiz.ed.The assurance strategy of transaction atomity and global deadlock resolution algorithm are also discussed in this thesis.At end of this thesis,based on domestic experiences and overseas experiences,a new multidatabase system model is presented by combining multidatabase system and CORBA technology,and security management mechanism is introduced in this model.