Ela Hunt - Böcker

This yearmarks anexciting time in the XML-database space:XQueryis moving closer to becoming a full W3C Recommendation, and the "Big 3" database vendors (IBM, Oracle, Microsoft) are expected to release XQuery support in theirrelationalDBMSs,joininganumberofexistingopensourceandcommercial products. Thus, we are very pleased to feature an industrial paper (describing theXML-speci?cfeaturesofMicrosoftSQLServer)aswellas14researchpapers. XSym's focus this year was on building XML repositories, and papers discussed the following topics: indexing support for the evaluation of XPath and XQuery; benchmarks and algorithms for XQuery and XPath evaluation; algorithms for constraint satisfaction checking, information extraction, and subtree matching; and applications of XML in information systems. This year, XSym also coordinated its e?orts with the Database and P- gramming Languages Symposium, DBPL 2005. The resulting program included not only presentations of the papers in this proceedings, but also a joint DBPL- XSym keynote talk by Giuseppe Castagna, developer of the CDuce language for XML processing, and a joint panel on open XML research problems and challenges.The organizers would like to express their gratitude to the XSym Program Committee and external reviewers for their e?orts in providing very thorough evaluationsofthesubmittedpapersundersigni?canttimeconstraintsandto- crosoftfortheirsponsorshipandfortheuseoftheMicrosoftConferenceMana- ment Toolkit. We would also like to thank Gavin Bierman and Christoph Koch, the organizersof DBPL, for their e?orts andtheir willingness to coordinate with us. These proceedings are dedicated to Alberto Mendelzon who sadly passed awaythisyear.Asastrongsupporterofandactivecontributortothissymposium series he will always remain in our memory.

The theme of the XML Database Symposium (XSym) is the convergence of database technology with XML technology. Since the first International XML Symposium in 2003, XSym has continued to provide a forum for academics, practitioners, users and vendors to discuss the use of and synergy between advanced XML technologies. XSym 2006 received 32 full paper submissions. Each submitted paper underwent a rigorous review by independent referees. These proceedings represent a collection of eight excellent research papers. Their focus is on building XML repositories and covers the following topics: XML query processing, caching, indexing and navigation support, structural matching, temporal XML, and XML updates. The organizers would like to express their gratitude to the XSym program c- mittee for their efforts in providing very thorough evaluations of the submitted papers under significant time constraints. We also would like to thank Microsoft for their sponsorship and for the use of the Microsoft Conference Management Toolkit, and the local organizers, especially, Kyuseok Shim, for all they did to make XSym a pleasant and successful event. July 2006 Sihem Amer-Yahia Zohra Bellahsene Jeffrey Xu Yu Ela Hunt Rainer Unland

Since its first edition in 2003, the XML Database Symposium series (XSym) has been a forum for academics, practitioners, users and vendors to discuss the use of and synergy between databases and XML. The previous symposia have provided opportunities for timely discussions on a broad range of topics pertaining to the theory and practice of XML data management and its applications. XSym 2007 continues this tradition with a program consisting of three research sessions, two keynote talks and a panel. We received 28 full paper submissions, out of which 8 were accepted for publication in these proceedings. Each submitted paper underwent a rigorous and careful review by a minimum of 4 independent referees. The contributions in these proceedings are a fine sample of the very best current research in XPath and XQuery processing, XML Updates, Temporal XML and Constraints. This volume also contains two invited short papers by the XSym 2007 keynote speakers: Leonid Libkin (University of Edinburgh, UK) contributed a thorough discussion of Normalization Theory for XML, while Erhard Rahm (University of Leipzig, Germany) contributed an interesting overview of the work on Dynamic Fusion of Web Data carried out at his - search group. This year, XSym will top its program off by an exciting panel with the title “The Generation Y of XML Schema Matching”. It was proposed and is organized by Avigdor Gal from Technion – Israel Institute of Techn- ogy.