 solid progress.
MK&gt; Delighted you think so
.    The ideas of having "generic relationship concept" ("relationship type"
in normal data modelling parlance), and "relationship instance" (just
"relationship" in normal data modelling parlance) make good sense, and fit
in well with the normal data modelling terminology many people use. It does,
however, mean that the traditional "entity - relationship diagram (ERD)" now
becomes an "entity - relationship type diagram".

MK&gt;  I believe the most natural inte