XPathLog is a logic-based language for manipulating and integrating XML data. It extends the XPath query language with Prolog-style variables. Due to the close relationship with XPath, the semantics of rules is easy to grasp. XPathLog defines a semantics for XPath expressions in rule heads, declaratively specifying how to create and update XML trees and nodes. In this paper, we show how XPathLog can be used to manipulate and restructure a database containing several XML trees. By linking subtrees, fusing elements and defining synonyms, data can be restructured and integrated into result trees. We illustrate the practicability of the approach by excerpts of a case study done with the LoPiX system.

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Extended versions can be found in the Habilitation thesis and in Theory and Practice of Logic Programming, 2004.
Further documentation can be found on the LoPiX project homepage.