[HACKERS] PL/pgSQL proposal: using list of scalars in assign stmts, fore and fors stmts
Hello
Now, statements EXECUTE INTO and SELECT INTO allow using list of scalars.
FORe and FORs allow only ROW o RECORD VARIABLE. I'll plan and I did it
enhance this stmts:
for := FOR target IN {SELECT | EXECUTE} ... LOOP
target := {row|record|comma separated list of scalar vars}
assign := target2 ':=' expression
target2 := {row|record|variable|'ROW(' comma separated list of scalar vars
')'}
for example:
CREATE OR REPLACE FUNCTION test(OUT _rc, OUT _x varchar, OUT _y varchar)
RETURNS SETOF RECORD AS $$
DECLARE _r RECORD;
BEGIN
rc := 0;
-- old style;
FOR _r IN SELECT generate_series AS x, generateseries + 1 AS y FROM
generate_series(1,4) LOOP
_rc := _rc + 1; _x := _r.x; _y := _r.y;
RETURN NEXT;
END LOOP;
-- new one
FOR _x,_y IN SELECT generate_series, generateseries + 1 FROM
generate_series(1,4) LOOP
_rc := _rc + 1;
RETURN NEXT;
END LOOP;
-- new two
FOR _r IN SELECT generate_series AS x, generateseries + 1 AS y FROM
generate_series(1,4)LOOP
_rc := _rc + 1; ROW(_x,_y) := _r;
RETURN NEXT;
END LOOP;
RETURN;
END; $$ LANGUAGE plpgsql;
any comments?
Regards
Pavel Stehule
_
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Re: [HACKERS] PL/pgSQL proposal: using list of scalars in assign stmts, fore and fors stmts
Pavel Stehule [EMAIL PROTECTED] writes:
for := FOR target IN {SELECT | EXECUTE} ... LOOP
target := {row|record|comma separated list of scalar vars}
This part seems all right to me.
assign := target2 ':=' expression
target2 := {row|record|variable|'ROW(' comma separated list of scalar vars
')'}
As I already said on -patches, I consider this a bad idea. It's too
error prone (because there's no easy way of seeing what the field order
will be). And it doesn't add anything that you can't do now. I think
a series of var = rec.field assignments is a preferable way to do it.
regards, tom lane
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Re: [HACKERS] PL/pgSQL proposal: using list of scalars in assign stmts, fore and fors stmts
On Thu, Dec 22, 2005 at 10:18:16AM +0100, Pavel Stehule wrote:
Hello
Now, statements EXECUTE INTO and SELECT INTO allow using list of scalars.
FORe and FORs allow only ROW o RECORD VARIABLE. I'll plan and I did it
enhance this stmts:
for := FOR target IN {SELECT | EXECUTE} ... LOOP
target := {row|record|comma separated list of scalar vars}
assign := target2 ':=' expression
target2 := {row|record|variable|'ROW(' comma separated list of scalar
vars ')'}
How about:
target2 := {row|record|variable|'[ROW](' comma separated list of scalar vars
')'}
instead, where the ROW is optional?
Cheers,
D
--
David Fetter [EMAIL PROTECTED] http://fetter.org/
phone: +1 415 235 3778
Remember to vote!
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Re: [HACKERS] PL/pgSQL proposal: using list of scalars in assign stmts, fore and fors stmts
David Fetter [EMAIL PROTECTED] writes:
How about:
target2 := {row|record|variable|'[ROW](' comma separated list of scalar
vars ')'}
instead, where the ROW is optional?
If we're going to do this at all (which I'm still agin), I think the ROW
keyword is important to minimize ambiguity. If you are allowed to start
a statement with just (x, ... then there will be way too many
situations where the parser gets confused by slightly bad input,
resulting in way-off-base syntax error reports. Or worse, no syntax
error, but a function that does something else than you expected.
I know that ROW is optional in the bit of SQL syntax that this proposal
is based on, but that's only because the SQL spec says we have to, not
because it's a good idea.
regards, tom lane
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