This project was about the extension of a purely algebraic XQuery compiler (Pathfinder) with an infrastructure for implicit score propagation. This is used to implement a subset of XQuery—Full Text, employing the PF/Tijah index for Full Text search.

It was shown that a flexible framework for implicit score propagation can be implemented easily —i.e., minimally invasive— on top of the Pathfinder compiler. The described prototype implementation can be parametrised with different scoring model functions, and should be adaptable to alternative database back-ends and Full Text engines.

During the project, various systematic problems that arise from implicit score propagation have been pointed out, rising the question whether such an approach is useful in general. Flaws in the design of the XQuery language were described that thwart more flexible extensions at the user level.

The PhD thesis “Pathfinder - Full Text: Extending a Purely Relational XQuery Compiler with a Scoring Infrastructure for XQuery Full Text” comprehends the findings of this project.


  • Leonard Worteler (adopted the XQFT parser from BaseX)
  • Stefan Klinger

Institutions involved:

  • DBIS
  • GK