Re: ARRAY vars (was Enable pl/python to return records based on multiple OUT params)

On Tue, 2008-11-04 at 14:05 -0500, David Blewett wrote:
> On Sat, Nov 1, 2008 at 7:52 AM, Hannu Krosing <hannu@2ndquadrant.com> wrote:
> > On Sat, 2008-11-01 at 06:13 +0200, Hannu Krosing wrote:
> >> attached is a patch which enables plpython to recognize function with
> >> multiple OUT params as returning a record
> >
> > Overrides previous patch.
> >
> > Fixed some bugs, added regression tests.
>
> Hi Hannu:
>
> I was wondering if it would be possible to get plpython to convert IN
> parameters of type ARRAY to Python lists? I see some example functions
> here [1], but it would be nice if it was done automatically.

This is one thing I definitely will do, praobably right after getting
ANY* to work, maybe even before, if getting ANY* to work requires too
many changes.

One open question is how to translate arrays with non-default subscript
values

Quote: "Subscripted assignment allows creation of arrays that do not use
one-based subscripts. For example one might assign to myarray[-2:7] to
create an array with subscript values running from -2 to 7."

Should I just shift it to standard python tuple, or would it be better
to return it as a dictionary with keys from -2 to 7

sample:

hannu=# create table ta(ia int[]);
CREATE TABLE
hannu=# insert into ta values('{27000,27000}');
INSERT 0 1
hannu=# update ta set ia[-2:1] = '{-2,-1,0,1}';
UPDATE 1
hannu=# select * from ta;
            ia
--------------------------
 [-2:2]={-2,-1,0,1,27000}
(1 row)


and if I do return a dictionary , the after this

hannu=# update ta set ia[7:7] = '{7}';
UPDATE 1
hannu=# select * from ta;
                       ia
------------------------------------------------
 [-2:7]={-2,-1,0,1,27000,NULL,NULL,NULL,NULL,7}
(1 row)

should the returned python dict have keys 3-6 with None, or could they
just be omitted ?



Actually I have quite long todo list (attached) of what I'd like to do
with pl/python, but I'm not sure how much will be accepted in 8.4 under
current commitfest/feature freeze scheme.

Anyway, I should put that up on wiki for comments.

> David
>
> 1. http://archives.postgresql.org/pgsql-general/2007-01/msg01417.php
>
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