>I don't think Ted talks specifically about Cache', but about OR Mapping in general.

Yes! And this is a key why we choose Cache': There is NO O-R mapping in Cache' at all.
I believe it will be interesting for you to look at their unified data architecture concept: http://www.intersystems.com/cache/technology/components/uda/index.html
In short, ALL data is defined as persistent classes. Once defined each class automatically can be queryied (or projected) as SQL-table.

This is NOT a slow SQL emulation over instantiated objects and this is NOT object mapping over relational tables.
The data is actually stored in sparse arrays which are used directly for both object and SQL access.

(In fact, Cache' also allows direct access to storage arrays, which one can use for fast bulk load, for example. This is something similar to our C programs that write DBFs as binary files while more simple as we don't need to deal with physical file format.)