Recursive queries using object relational mapping

Abstract

Recent years witnessed continuous development of database query languages and object relational mappers. One of the research fields of interest are recursive queries. The first implementations of such queries for SQL has been introduced by Oracle in 1985. However, it was the introduction of recursive Common Table Expressions into the SQL:99 standard that made the research on this topic more popular. Currently most of the popular DBMS implements recursive queries, but there are no object relational mappers that support such queries. In this paper we propose extending existing ORMs with recursive CTE's support. A prototype of such an extension has been implemented in SQLObject mapper for the Python language. Tests have been conducted with PostgreSQL 8.4 database. Furthermore, recursive queries written using CTEs amount to be too complex and hard to comprehend. Our proposal overcomes this problem by pushing the formulation of recursive queries to a higher abstraction level, which makes them significantly simpler to write and to read. © 2010 Springer-Verlag Berlin Heidelberg.