Keynote Address -- Distributed XML Query Processing -- XML Query Processing -- Approximate Joins for XML Using g-String -- Linear Computation of the Maximum Simultaneous Forward and Backward Bisimulation for Node-Labeled Trees -- Extending the Tractability Results on XPath Satisfiability with Sibling Axes -- Extending XQuery with a Pattern Matching Facility -- XML Update and Applications -- A Schema-Based Translation of XQuery Updates -- EBSL: Supporting Deleted Node Label Reuse in XML -- Lessons Learned from DB2 pureXML Applications: A Practitioner's Perspective -- Searchable Compression of Office Documents by XML Schema Subtraction -- XML Modeling -- Fast Detection of Functional Dependencies in XML Data -- TP+Output: Modeling Complex Output Information in XML Twig Pattern Query -- Promoting the Semantic Capability of XML Keys.

Since its first edition in 2003, the XML Database Symposium series (XSym) has been a forum for academics, practitioners, users and vendors, allowing all to discuss the use of and synergy between database management systems and XML. The symposia have provided many opportunities for timely discussions on a broad range of topics pertaining to the theory and practice of XML data management and its applications. XSym 2010 continued this XSym tradition with a program consisting of 11 papers and a keynote shared with the 36th International Conference on Very Large Data Bases (VLDB 2010). We received 20 paper submissions, out of which 8 papers were accepted as full papers, and 3 as short papers. Each submitted paper underwent a rigorous and careful review by four referees. The contributions in these proceedings are a fine sample of the current research in XML query processing, including XPath satisfiability, approximate joins, pattern matching, linear index construction for trees, dynamic labeling, and XQuery update translation based on schema. The papers focus on recent advances in detecting fu- tional dependencies, modeling complex XML twig pattern output, promoting sem- tics capability of XML keys, and searchable compression of Microsoft office do- ments. In addition, we include a paper that shares lessons learned from real XML database development.