This thesis covers the conception of a visual query and transformation
interface for XML, based on pattern matching. The interface is a front end
for Xcerpt
[bry02gentle], a descriptive query and
transformation language for XML. The system aims at easing the task of
querying semi-structured data for the casual end-user who often feels
uncomfortable with textual programming languages. The goal of this thesis is
to fill the gap between the interactive nature of current research on XML
query systems, like QURSED
[petropoulos02qursed]
and BBQ
[munroe00bbq], and research about visual
query languages for XML and object oriented database systems. While visual
languages usually provide a good approach to statical representation of
program or query structure, the editing and browsing of programs is rarely
covered by visual languages. Interactive query systems on the other hand do
not provide a static view of programs that can be understood or stored
outside the context of the query environment. In contrast, the visual Xcerpt
interface presented in this thesis covers both aspects: visual representation
of Xcerpt programs and an editor model tailored for this view.
Due to the widespread acceptance of QBE-like [zloof77query] database interfaces by casual users, an
intuitive pattern based approach for querying XML is desirable. VisXcerpt,
the system presented in this thesis, fulfills this requirement.