However, we have pretty clear ideas of how to continue. There is a need to implement and test out preliminary results. They are especially prevelent in conjunction with data warehouses. We are currently studying issues relating to aggregate query optimization. We are interested both in characterizing equivalences and in rewriting aggregate queries with views.
Theory is well-understood.
We are continuing to extend our results to other important cases. Research in this area is mostly theoretical, but could also involve implementation of algorithms. The W3Graph System , a.k.a. Quest, was developed before the advent of XML as a standard for adding markup to Web documents. Then, Web pages were queried using a graphical query language.