Re: Allow COPY to use parameters

>>>>> "Merlin" == Merlin Moncure <mmoncure(at)gmail(dot)com> writes:

Merlin> Note, the biggest pain point I have with COPY is not being able
Merlin> to parameterize the filename argument.

Second proof of concept attached. This goes so far as to allow
statements like:

do $$
declare t text := 'bar'; f text := '/tmp/copytest.dat';
begin copy (select t, now()) to (f) csv header; end;
$$;

Also "copy foo to $1" or "copy (select * from foo where x=$1) to $2" and
so on should work from PQexecParams or in a plpgsql EXECUTE.

(I haven't tried to parameterize anything other than the filename and
query. Also, it does not accept arbitrary expressions - only $n, '...'
or a columnref. $n and '...' can have parens or not, but the columnref
must have them due to conflicts with unreserved keywords PROGRAM, STDIN,
STDOUT. This could be hacked around in other ways, I guess, if the
parens are too ugly.)

--
Andrew (irc:RhodiumToad)