Nuwee Wiwatwattana

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This paper describes the overall design and architecture of the Timber XML database system currently being implemented at the University of Michigan. The system is based upon a bulk algebra for manipulating trees, and natively stores XML. New access methods have been developed to evaluate queries in the XML context, and new cost estimation and query(More)
XML has a tree-structured data model, which is used to uniformly represent structured as well as semi-structured data, and also enable concise query specification in XQuery, via the use of its XPath (twig) patterns. This in turn can leverage the recently developed technology of structural join algorithms to evaluate the query efficiently. In this paper, we(More)
With increasing amounts of data being exchanged and even generated or stored in XML, a natural question is how to perform OLAP on XML data, which can be structurally heterogeneous (e.g., parse trees) and/or marked-up text documents. A core operator for OLAP is the data cube. While the relational cube can be extended in a straightforward way to XML, we argue(More)
XML has become ubiquitous, and XML data has to be managed in databases. The current industry standard is to map XML data into relational tables and store this information in a relational database. Such mappings create both expressive power problems and performance problems.In the T<sc>IMBER</sc> [7] project we are exploring the issues involved in storing(More)
XML schema design has two opposing goals: elimination of update anomalies requires that the schema be as normalized as possible; yet higher query performance and simpler query expression are often obtained through the use of schemas that permit redundancy. In this paper, we show that the recently proposed MCT data model, which extends XML by adding colors,(More)
Organelle DB ( is a web-accessible relational database presenting a supplemented catalog of organelle-localized proteins and major protein complexes. Since its release in 2004, Organelle DB has grown by 20% to encompass over 30,000 proteins from 138 eukaryotic organisms. Each protein in Organelle DB is presented with its(More)
To efficiently utilize the growing body of available protein localization data, we have developed Organelle DB, a web-accessible database cataloging more than 25,000 proteins from nearly 60 organelles, subcellular structures and protein complexes in 154 organisms spanning the eukaryotic kingdom. Organelle DB is the first on-line resource devoted to the(More)
Data warehousing accounts for a significant fraction of database use today. As XML becomes ever more popular, more and more XML data finds its way into data warehouse repositories. This paper examines the modeling mismatch between the tree structure of XML data model and the multidimensional model of a typical data warehouse, and proposes an XML warehouse(More)
XML is now widely used and management of XML data has become important. To this end, there has been work on the native management of XML data in a database to utilize the different capabilities of such a system like transaction management and indexing structures. At the heart of such a native XML database is the query evaluator, which provides access(More)