Abstract
There have been many attempts to create software that would allow the users to design SQL queries visually, even though it is not very natural to handle relations and relational algebra (the theoretical background of SQL) this way. But the RDF data format is based on directed labeled graphs, whose visual representation is very natural.
We have created an RDF visualizer and tried to extend it to support query construction. It turned out that the nature of current RDF query languages only allows some basic support but prevents creation of a more sophisticated system.
This articles describes our query generator and discusses the limiting factors.