Progress in database search strategies

Retrieval speed and precision ultimately determine the success of any database system. This article outlines the challenges posed by distributed and heterogeneous database systems, including those that store unstructured data, and surveys recent work. Much work remains to help users retrieve information with ease and efficiency from a heterogeneous environment in which relational, object-oriented, textual, and pictorial databases coexist. The article outlines the progress that has been made in query processing in distributed relational database systems and heterogeneous and multidatabase systems.<>