On the Expressive Power of Node Construction in XQuery

In the relational model it has been shown that the flat relational algebra has the same expressive power as the nested relational algebra, as far as queries over flat relations and with flat results are concerned [6]. Hence, for each query that uses the nested relational model and that, with a flat table as input always has a flat table as output, there exists an equivalent flat query that only uses the flat relational model. In analogy, we study a related flat-flat problem for XQuery: for each expression containing operations that construct new nodes and whose XML result contains only original nodes, there exists an equivalent “flat” expression in XQuery that does not construct new nodes. Categories and Subject Descriptors H.2 [Information Systems]: Database Management; H.2.3 [Database Management]: Languages—Query languages Keywords XQuery,XML,Expressive power

• Type: Conference
• Year: 2005
• Where: WEBDB
• Authors: Wim Le Page, Jan Hidders, Philippe Michiels, Jan Paredaens, Roel Vercammen
• Keywords: Internet Technology, Nested Relational Algebra, Relational Algebra, Relational Model, WEBDB 2005