Algebraic Languages for XML Databases

XML is becoming increasingly popular as a means of exchanging a wide variety of data on the web. It is anticipated that in the future, many websites will be built from XML documents. XML databases would be required to manage these websites and also provide a way for users to search their contents. In this paper we give an overview of the development of query algebras from the original relational algebra to the algebras for extended-relational, object-oriented and semi-structured or XML data models. We discuss in detail and provide a cross comparison of the various algebras proposed for XML. We also discuss the implementation of a particular algebra in the context of MMXDB, which is a main-memory XML database system that we are developing