Currently, it is difficult to visualize databases with hundreds of tables and thousands of columns. For such large databases (and also for smaller ones) it would be a relief to be able to switch between displaying all columns and displaying only the PK columns. Maybe even a possibility to display without columns at all. So there should be a global switching possibility for the whole chart. And finally it would be helpful if you could expand and collapse a chart without columns or only with the PK individually.