Determining Correct View Update Translations via Query Containment

Abstract

Given an intensional database (IDB) and an extension database the view update problem translates updates on the IDB into updates on the EDB. One approach to the view update problem uses a translation langauge to specify the meaning of a view update. In this paper we prove properties of a translation language. This approach to the view update problem studies the expressive power of the translation language and the computational cost of demonstrating properties of a translation. We use an active rule based database language for specifying translations of view updates. This paper uses the containment of one datalog program (or conjunctive query) by another to demonstrate that a translation is semantically correct. We show that the complexity of correctness is lower for insertion than deletion. Finally, we discuss extensions to the translation language.