On Tue, Apr 28, 2015 at 9:58 AM, Stephen Frost <sfr...@snowman.net> wrote:
> * Peter Geoghegan (p...@heroku.com) wrote: > > On Tue, Apr 28, 2015 at 9:42 AM, Stephen Frost <sfr...@snowman.net> > wrote: > > > I agree with that, but how are NEW and OLD ambiguous? NEW is clearly > > > the tuple being added, while OLD is clearly the existing tuple. > > > > Yes, but EXCLUDED is neither the tuple being added, nor is it the new > > tuple. It's something else entirely. > So? I see this as a prime case for choosing practicality/functionality over precision. If I was to pick 2 words I would probably pick "PROPOSED" and "EXISTING". But, the syntax is already verbose and being able to use a three-letter reference has its own appeal. > I don't see that, it's exactly the tuple attempting to be inserted. I > agree that it might not be the tuple originally in the INSERT statement > due to before triggers, but there isn't an alias anywhere for that. > > Now, in 99% of cases there aren't going to be before triggers so I'm not > particularly worried about that distinction, nor do I think we need to > provide an alias for the tuple from the INSERT piece of the clause, but > to say that EXCLUDED isn't the tuple being added doesn't make any sense > to me, based on how I read the documentation proposed here: > > > http://postgres-benchmarks.s3-website-us-east-1.amazonaws.com/on-conflict-docs/sql-insert.html This example exemplifies the poorness of the proposed wording, IMO: [...] SET dname = EXCLUDED.dname || ' (formerly ' || TARGET.dname || ')' NEW.dname || '(formerly ' || OLD.dname || ')' reads perfectly well. Yes, this is an isolated example...but am I missing the fact that there is a third tuple that needs to be referenced? If there are only two the choices of NEW and OLD seem to be both easily learned and readable. David J.
