Now showing items 1-12 of 12

    • Algebraic optimization of nested XPath expressions 

      Brantner, M; Kanne, CC; Moerkotte, G; Helmer, S (ICDE, 2006)
      The XPath language incorporates powerful primitives for formulating queries containing nested subexpressions which are existentially or universally quantified. However, even the best published approaches for evaluating ...
    • Algebraic Translation and Optimization of (Nested) XPath Expressions 

      Brantner, M; Kanne, CC; Helmer, S; Moerkotte, G (IEEE, 2006)
      The XPath language incorporates powerful primitives for formulating queries containing nested subexpressions which are existentially or universally quantified. However, even the best published approaches for evaluating ...
    • Anatomy of a native XML base management system 

      Fiebig, T; Helmer, S; Kanne, CC; Moerkotte, G; Neumann, J; Schiele, R; Westmann, T (Springer Verlag (Germany), 2002)
      Several alternatives to manage large XML document collections exist, ranging from file systems over relational or other database systems to specifically tailored XML base management systems. In this paper we give a tour ...
    • Evaluating lock-based protocols for cooperation on XML documents 

      Helmer, S; Kanne, CC; Moerkotte, G (Association for Computing Machinery; 1999, 2004)
      We discuss four different core protocols for synchronizing access to and modifications of XML document collections. These core protocols synchronize structure traversals and modifications. They are meant to be integrated ...
    • Full-fledged algebraic XPath processing in natix 

      Brantner, M; Helmer, S; Kanne, CC; Moerkotte, G (ICDE, 2005)
      We present the first complete translation of XPath into an algebra, paving the way for a comprehensive, state-of-the-art XPath (and later on, XQuery) compiler based on algebraic optimization techniques. Our translation ...
    • Kappa-Join: Efficient Execution of Existential Quantification in XML Query Languages 

      Brantner, M; Helmer, S; Kanne, CC; Moerkotte, G (Springer, 2006)
      XML query languages feature powerful primitives for formulating queries, involving comparison expressions which are existentially quantified. If such comparisons involve several scopes, they are correlated and, thus, become ...
    • Lock-based Protocols for Cooperation on XML Documents 

      Helmer, S; Kanne, CC; Moerkotte, G (IEEE, 2003)
      The extensible Markup Language (XML) is well accepted in several different Web application areas. As soon as many users and applications work concurrently on the same collection of XML documents - e.g. on an XML database ...
    • Natix: A technology overview 

      Fiebig, T; Helmer, S; Kanne, CC; Moerkotte, G; Neumann, J; Schiele, R; Westmann, T (Springer, 2002)
      Several alternatives to manage large XML document collections exist, ranging from file systems over relational or other database systems to specifically tailored XML base management systems. In this paper we review Natix, ...
    • Optimized Translation of XPath into Algebraic Expressions Parameterized by Programs Containing Navigational Primitives 

      Helmer, S; Kanne, CC; Moerkotte, G (IEEE Computer Society, 2002)
      We propose a new approach for the efficient evaluation of XPath expressions. This is important, since XPath is not only used as a simple, stand-alone query language, but is also an essential ingredient of XQuery and XSLT. ...
    • Timestamp-based protocols for synchronizing access on XML documents 

      Helmer, S; Kanne, CC; Moerkotte, G (Springer, 2004)
      The eXtensible Markup Language (XML) is well accepted in many different application areas. As a consequence, there is an increasing need for storing XML documents persistently. As soon as many users and applications work ...
    • XML-Datenbanken und ihre Anwendung 

      Helmer, S; Kanne, CC; Moerkotte, G (2003)
      Due to its fast proliferation,the amount of XML data is steadily increasing and XML-based applications become more and more complex. This requires effective and efficient methods to manage large amounts of persistent XML. ...
    • XQuery Processing in Natix with an Emphasis on Join Ordering 

      May, N; Helmer, S; Kanne, CC; Moerkotte, G (ACM, 2004)
      We give an overview on how XQuery processing works in our native XML database system Natix. After a brief description of the query compiler we focus on the aspect of join ordering when generating query execution plans. ...