A Query Language for Rational Tree Structures

Abstract

Traditional query languages such as SQL have been highly successful in both the areas of academia and industry. One of the compelling reasons for this high level of success is the declarative and intuitive manner in which queries could be constructed using such query languages. Additionally, the generic nature of their update operations makes it much easier for the user to specify update queries. This works well for performing queries to retrieve and update data in databases based on the relational model. However, the demands for storing more complex data other than in the form of flat tables are increasing, as research continues into XML and object-oriented databases. Parallel to these demands is also the requirement for a more powerful query language that would enable the retrieval and update of these more complex databases in an intuitive and declarative manner. We introduce the idea of a higher-level intermediary language that allows the querying and update of rational-tree type data (as found in XML datastores and object-oriented databases). We present elements of a language that allows declarative query operations for both querying and update operations in a generic manner.