XPath-Logic, XPathLog, and LoPiX: a Logical Approach to XML and XML Data Integration (2000-2004)

The XPathLog/LoPiX project (2000-2003) is the continuation and migration of the F-Logic/Florid project to XML. Due to many similarities between the F-Logic and XPath languages, F-Logic is a natural candidate for a migration to XML/XPath: The XPathLog language is a crossbreed between XPath and F-Logic, i.e., it extends XPath with variable bindings to an XML querying and data manipulation language. XPathLog assigns a declarative constructive semantics to XPath expressions for specifying database updates. The LoPiX system which implements XPathLog is based on the Florid system. The research on data integration is now continued with LoPiX.

One of the main results --apart from the fact that XPathLog/LoPiX is the first implementation of updates in an XML database language-- is that the DOM/XML Query Data Model is not suitable for updating and integrating XML data. Instead, XPathLog/LoPiX use the XTreeGraph data model which allows for representing multiple, overlapping XML trees in an internal database. Result trees are then defined as views over the XTreeGraph database.

XPath-Logic and XPathLog

XPathLogic is a logic which is interpreted wrt. XML documents. Its Horn fragment, XPathLog, provides a logic-based language for manipulating and integrating XML data.

• Technical Report/Habilitation Thesis A Logic-Based Approach to XML Data Integration (2001).
• Journal version of XPathLog: XPath-Logic and XPathLog: A Logic-Programming Style XML Data Manipulation Language, Wolfgang May; Theory and Practice of Logic Programming 4(3), pp. 239-287, 2004.
• the Mondial Case Study: XML Information Integration
• A first, short presentation of the language appeared in
  XPathLog: A Declarative, Native XML Data Manipulation Language, Wolfgang May; International Database Engineering & and Applications Workshop (IDEAS), July 2001; IEEE CS Press.
• LoPiX has been presented at Intl. Conf. on Very Large Databases (VLDB) - Demonstration Track, Sept. 2001.
• The formal aspects of the language:
  A Rule-based Querying and Updating Language for XML, Wolfgang May; Workshop on Databases and Programming Languages (DBPL), Sept. 2001 (Springer LNCS 2397).
• Considerations on a data model for updating XML:
  On an XML Data Model for Data Integration, Wolfgang May, Erik Behrends; Intl. Workshop on Foundations of Models and Languages for Data and Objects (FMLDO), Sept. 2001.
• First considerations on XML data integration have been discussed in Integration of XML Data in XPathLog, Wolfgang May, CAiSE Workshop Data Integration over the Web (DIWeb), June 2001.
• Aspects of generic data integration have been investigated in A Framework for Generic Integration of XML Data Sources, Wolfgang May; International Workshop on Knowledge Representation meets Databases (KRDB), Sept. 2001.
• A short report in german language has been published in Datenintegration in XML - ein regelbasierter Ansatz, Wolfgang May; Datenbank-Spektrum, 6/2003.

XPathLog and LoPiX have been used in 2002/03 for a first prototype for evaluating XLinks in the LinXIS project.

LoPiX: Logic Programming in XML

The LoPiX system is an implementation of the XML querying and data manipulation language XPathLog. It is free for evaluation, research and teaching purposes, but not in the public domain.

The .tar-file comes along with the executable (for different operating systems, currently solaris, SuSe Linux, and RedHat Linux), documentation, and examples.

• Download lopix.tar.gz (Version 3.0)
  Note that this version 3.0 required gcc and glibc in the 2000-2003 versions.
• The successor, Florid 4.x, still optionally supports the complete LoPiX behavior. Its homepage can be found at Freiburg University (maintenance ended about 2007).

Unpacking:

First unpack the compressed archive with the command
gunzip lopix.tar.gz
Then you get the file lopix.tar which is extracted with
tar xf lopix.tar
After this you get the following directory structure

lopix/bin
lopix/environment
lopix/sgml
lopix/lopix-doc
lopix/lopix-examples

The directory lopix/bin contains binaries for solaris and linux. Rename the one you intend to use to lopix. The directory lopix/lopix-doc contains a postscript version of the user manual (lopix.ps).

Instructions for installing LoPiX on your system can be found in the user manual.

• lpx2tex.pl: A perl script for producing a LaTeX documentation from LoPiX programs.