A Component-Based Framework for the Integration and Exploration of XML Sources

Handling the interoperability issues in multiple, heterogeneous XML sources is central in XML data management and mining. In this chapter, we present a framework for the intensional integration and exploration of XML sources. Specifically, we propose a three-layer framework aimed at extracting interschema knowledge from the available sources, constructing a hierarchy based on the extracted knowledge to represent the sources at different abstraction levels, and finally organizing and exploring the sources through the constructed hierarchy. We also describe possible implementations of each of the three layers, focusing on the extraction of intensional interschema properties, the intensional integration of XML sources, and the clustering of XML schemas. In order to better handle the complexity of its activities, the proposed framework has been designed by means of the layers architecture patterns and the component-based development paradigm.

XQBE

This Chapter describes a visual framework; called XQBE; that covers the most important aspects of XML data management; spanning the visualization of XML documents; the formulation of queries; the representation and specification of document schemata; the definition of integrity constraints; the formulation of updates; and the expression of reactive behaviors in response to data modifications. All these features are strongly unified by a common visual abstraction and a few recurrent paradigms; so as to provide a homogeneous and comprehensive environment that allows even users without advanced programming skills to deal with nontrivial XML data management and transformation tasks. The intrinsic ambiguity inherent in any visual representation of richly expressive languages required a considerable effort of formalization in the semantics of XQBE that eventually lead to a solution with major advantages in terms of intuitiveness. In other words; this means that the unique (and unambiguous) effect of a statement is the one the user would expect.

A Deterministic Approach to XML Query Processing with Efficient Support for Pure and Negated Containments

This article reports the result of the author’s recent work on XML query processing/optimization, which is a very important issue in XML data management. In this work, in order to more effectively and efficiently handle XML queries involving pure and/or negated containments, a previously proposed deterministic optimization approach is largely adapted. This approach resorts to heuristic-based deterministic transformations on algebraic query expressions in order to achieve the best possible optimization efficiency. Specialized transformation rules are thus developed, and efficient implementation algorithms for pure and negated containments are presented as well. Experimental study confirms the validity and effectiveness of the presented approach and algorithms in processing of XML queries involving pure and/or negated containments.

Data Integration Issues and Opportunities in Biological XML Data Management

There is a proliferation of research and industrial organizations that produce sources of huge amounts of biological data issuing from experimentation with biological systems. In order to make these heterogeneous data sources easy to use, several efforts at data integration are currently being undertaken based mainly on XML. Starting from a discussion of the main biological data types and system interactions that need to be represented, the authors deal with the main approaches proposed for their modelling through XML. Then, they show the current efforts in biological data integration and how an increasing amount of Semantic information is required in terms of vocabulary control and ontologies. Finally, future research directions in biological data integration are discussed.

XML Data Management in Object Relational Database Systems

Since the advent of XML, there has been significant research into integrating XML data management with Relational DBMS and Object Relational DBMS (ORDBMS). This chapter describes the XML data management capabilities in ORDBMS, various design approaches and implementation techniques to support these capabilities, as well as the pros and cons of each design and implementation approach. Key topics such as XML storage, XML Indexing, XQuery and SQL/XML processing, are discussed in depth presenting both academic and industrial research work in these areas.

XML Compression

To effectively reduce the redundancy and verbosity of XML data, various studies for XML compression have been conducted. Especially, XML data management systems and applications require the support of direct query processing and update on compressed XML data, the stream based compression/decompression, and the reduction of the size of the compressed data. In order to fully support the various aspects of XML compression, existing XML compression techniques should be carefully examined and the additional requirements for XML compression techniques should be considered. In this chapter, the authors first classify existing representative XML compression techniques according to their characteristics. Second, they explain the details of XML specific compression techniques. Third, they summarize the performance of the compression techniques in terms of the compression ratio and the compression and decompression time. Lastly, they present some future research directions.