A Better DBMS Matrix
I believe we'd be better served by a change in the vertical axis of the DBMS Matrix. Handling queries is not a valid way to classify DBMSs. Many DBMSs handle queries, including relational, object, and object-relational. Navigation performance is a way to classify DBMSs. If we draw a new matrix taking navigation into consideration, a clearer, more accurate picture results, as shown in the following figure. By the way, it is assumed that all DBMSs in this matrix handle queries. Nevertheless, I have noted this in the left axis just so there is not mistaking this fact.
This matrix indicates that if you have a business need for high performance on complex data, you should be looking at ODBMSs. It is terribly wrong to discount ODBMSs based on the erroneous idea that they do not handle queries. It is more accurate to see that they handle queries and provide high performance navigation for complex data -- often, that navigation involves queries.
More on the general topic: Stonebraker's DBMS Matrix