On Thu, Dec 17, 2009 at 1:37 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Andrew Dunstan <and...@dunslane.net> writes: >> Tom Lane wrote: >>> The problem with COPY FROM is that it hard-wires a decision that there >>> is one and only one possible result format, which I think we pretty >>> much proved already is the wrong thing. I'm not thrilled with "RETURNING >>> ARRAY" either, but we need to leave ourselves wiggle room to have more >>> than one result format from the same source file. > >> Well, we could have "RETURNING type-expression" with "text[]" supported >> for the first iteration. > >> In answer to Heiki's argument, what I wanted was exactly to return an >> array of text for each row. Whatever we have needs to be able to handle >> to possibility of ragged input (see previous discussion) so we can't tie >> it down too tightly. > > I think that there are two likely possibilities for the result format: > > * "Raw" data after just the de-escaping and column separation steps. > Array of text is probably the right thing here, at least for a text COPY > (doesn't seem to cover the binary case though). > > * The data converted to some specified row type.
Agreed. > "RETURNING type-expression" is probably not good since it looks more > like the second case than the first --- and in fact it could be outright > ambiguous, what if your data actually is one column that is a text > array? > > If we're willing to assume these are the *only* possibilities then we > could use "COPY FROM ..." for the first and "COPY RETURNING type-list > FROM ..." for the second. I'm a bit uncomfortable with that assumption > though; it seems likely that we'll want to shoehorn in some more > alternatives later. (Like, what about the binary case?) You might want to specify column names as well as well as types, in this second case. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
