These papers are organized in topical sections on reasoning about XML schemas and queries, aggregate queries, query evaluation, query rewriting and reformulation, semistructured versus structured data, query containment, consistency and incompleteness, and data structures.

Invited Papers.- Open Problems in Data-Sharing Peer-to-Peer Systems.- Approximations in Database Systems.- Bioinformatics Adventures in Database Research.- Reasoning about XML Schemas and Queries.- Incremental Validation of XML Documents.- Typechecking Top-Down Uniform Unranked Tree Transducers.- Structural Properties of XPath Fragments.- On Reasoning about Structural Equality in XML: A Description Logic Approach.- Aggregate Queries.- Containment of Aggregate Queries.- Auditing Sum Queries.- CRB-Tree: An Efficient Indexing Scheme for Range-Aggregate Queries.- Optimal Range Max Datacube for Fixed Dimensions.- Query Evaluation.- Processing XML Streams with Deterministic Automata.- Deciding Termination of Query Evaluation in Transitive-Closure Logics for Constraint Databases.- Query Rewriting and Reformulation.- Data Exchange: Semantics and Query Answering.- Reformulation of XML Queries and Constraints.- New Rewritings and Optimizations for Regular Path Queries.- Database Interrogation Using Conjunctive Queries.- Semistructured versus Structured Data.- On the Difficulty of Finding Optimal Relational Decompositions for XML Workloads: A Complexity Theoretic Perspective.- Generating Relations from XML Documents.- Query Containment.- Containment for XPath Fragments under DTD Constraints.- XPath Containment in the Presence of Disjunction, DTDs, and Variables.- Decidable Containment of Recursive Queries.- Containment of Conjunctive Queries with Safe Negation.- Consistency and Incompleteness.- Probabilistic Interval XML.- Condensed Representation of Database Repairs for Consistent Query Answering.- Typing Graph-Manipulation Operations.- Characterizing the Temporal and Semantic Coherency of Broadcast-Based Data Dissemination.- Data Structures.- An Efficient Indexing Scheme for Multi-dimensional Moving Objects.- Nearest Neighbors Can Be Found Efficiently If the Dimension Is Small Relative to the Input Size.