Polynomial time fragments of XPath with variables

Variables are the distinguishing new feature of XPath 2.0 which permits to select n-tuples of nodes in trees. It is known that the Core of XPath 2.0 captures n-ary first-order (FO) queries modulo linear time transformations. In this paper, we distinguish a fragment of Core XPath 2.0 that remains FO-complete with respect to n-ary queries while enjoying polynomial-time query answering. Categories and Subject Descriptors: H.2.3 [Languages]: Query Languages General Terms: Algorithms, Languages, Theory

• Type: Conference
• Year: 2007
• Where: PODS
• Authors: Emmanuel Filiot, Joachim Niehren, Jean-Marc Talbot, Sophie Tison
• Keywords: Database, N-ary Queries, PODS 2007, Polynomial-time Query Answering, XPath 2.0 Captures