Physical Sciences and Mathematics Commons^™

Windowed Pq-Grams For Approximate Joins Of Data-Centric Xml, Nikolaus Augsten, Michael H. Böhlen, Curtis Dyreson, Johann Gamper

Curtis Dyreson

In data integration applications, a join matches elements that are common to two data sources. Since elements are represented slightly different in each source, an approximate join must be used to do the matching. For XML data, most existing approximate join strategies are based on some ordered tree matching technique, such as the tree edit distance. In data-centric XML, however, the sibling order is irrelevant, and two elements should match even if their subelement order varies. Thus, approximate joins for data-centric XML must leverage unordered tree matching techniques. This is computationally hard since the algorithms cannot rely on a predefined …

Adding Temporal Constraints To Xml Schema, Faiz Currim, Sabah Currim, Curtis Dyreson, Richard T. Snodgrass, Steven W. Thomas, Rui Zhang

Curtis Dyreson

If past versions of XML documents are retained, what of the various integrity constraints defined in XML Schema on those documents? This paper describes how to interpret such constraints as sequenced constraints, applicable at each point in time. We also consider how to add new variants that apply across time, so-called non-sequenced constraints. Our approach supports temporal documents that vary over both valid and transaction time, whose schema can vary over transaction time. We do this by replacing the schema with a (possibly time-varying) temporal schema and replacing the document with a temporal document, both of which are upward compatible …

Metaxpath, Curtis Dyreson, Michael H. Böhen, Christian S. Jensen

Curtis Dyreson

This paper presents the METAXPath data model and query language. METAXPath extends XPath with support for XML metadata. XPath is a specification language for locations in an XML document it serves as the basis for XML query languages like XSLT and the XML Query Algebra.

The METAXPath data model is a nested XPath tree. Each level of metadata induces a new level of nesting. The data model separates metadata and data into different data spaces, supports meta-metadata and enables sharing of metadata common to a group of nodes without duplication. The METAXPath query language has a level shift operator to …