Object-Oriented Programming with Recursive Queries

Recursive queries are required in many object-oriented database applications. Among them we can mention Bill-Of-Material (BOM), various kinds of networks (transportation, telecommunication, etc.), processing semistructured data (XML, RDF), and so on. The support for recursive queries in current query languages is limited and lacks theoretical foundations. In this paper we present recursive query processing capabilities for object-oriented environments. They are part of Stack-Based Query Language (SBQL). SBQL offers powerful and flexible recursive querying capabilities due to the fact that recursive processing operators are fully orthogonal to other features of this language. This paper discusses corresponding SBQL constructs: variants of transitive closures, fixed point equations and recursive procedures/views. The paper is augmented by discussion concerning the state-of-the-art of current recursive querying capabilities.