Many DBs have some kind of RETURNING clause that allows to specify which columns of inserted/updated/deleted rows should be returned from a DML statement. We could also use this mechanism internally for fetching generated values after entity inserts/updates instead of doing full fetches.

I propose a syntax extension for DML statements: ('returning' expression (',' expression)*)?

Emulating this feature, although not easy, should be possible. We'd have to use our multi-table facilities for that purpose, which will first insert ids of entities to modify into a temporary table, then run the DML and finally run a select statement for the returning clause based on the data from the temporary table.