Interactive Query Formulation using Query By Navigation

Effective information disclosure in the context of databases with a large conceptual schema is known to be a non-trivial problem. In particular the formulation of ad-hoc queries is a major problem in such contexts. Existing approaches for tackling this problem include graphical query interfaces, query by navigation, query by construction, and point to point queries. In this report we propose an adoption of the query by navigation mechanism that is especially geared towards the InfoAssistant product. Query by navigation is based on ideas from the information retrieval world, in particular on the stratified hypermedia architecture. When using our approach to the formulations of queries, a user will first formulate a number of simple queries corresponding to linear paths through the information structure. The formulation of the linear paths is the result of the {\em explorative phase} of the query formulation. Once users have specified a number of these linear paths, they may combine them to form more complex queries. Examples of such combinations are: concatenation, union, intersection and selection. This last process is referred to as {\em query by construction}, and is the {\em constructive phase} of the query formulation process.