I think you should be able to select columns you want to show in the diagram, and hide the other behind a small ... Button. That way you can keep table box size

I think you should be able to select columns you want to show in the diagram, and hide the other behind a small ... Button. That way you can keep table box size small. A default of "show none" is probably sane for visibility, in particular if you have many tables or columns in the whole diagram