Re: Improving PL/PgSQL (was: Re: plpgsql defensive mode)

2014-09-06 20:08 GMT+02:00 Marko Tiikkaja <marko(at)joh(dot)to>:

> On 2014-09-06 7:56 PM, Pavel Stehule wrote:
>
>> 2014-09-06 19:54 GMT+02:00 Marko Tiikkaja <marko(at)joh(dot)to>:
>>
>>> Then that doesn't really solve our problem. Switching between two
>>> languages on a per-function basis, when both look exactly the same but
>>> have
>>> very different semantics would be a nightmare.
>>>
>>>
>> It is maximum what is possible
>>
>> use a different language instead
>>
>
> Sigh.
>
> OK, let's try and forget the cardinality assertions we've been talking
> about in the other thread(s). I seem to recall there being a generally
> welcoming atmosphere in the discussion about adding a set of pragmas (or
> options/whatever) to make some of PL/PgSQL's flaws go away, in a
> non-backwards compatible way. From the list here:
> https://wiki.postgresql.org/wiki/Improving_PL/PgSQL_(September_2014) do
> you think at least some of those would be reasonable candidates for these
> pragmas? Do you see others ones that are missing from this list?
>
> Please also keep discussion about ASSERT in the thread for that, and the
> suggestion under "Single-row operations" out of this.
>

SELECT .. INTO vs. TOO_MANY_ROWS

+1 .. possible every where
Variable assignments

+1 .. only in "defensive mode"
Single-row operations

+1 .. only in "defensive mode" without special syntax
EXECUTE and FOUND

-1 .. it is emulation of PL/SQL behave.. so introduction can do too high
unhappy surprise if somebody will migrate to Oracle -- the syntax is too
similar
OUT parameters

-1 .. to proposal .. It is in contradiction with current feature. Next it
is nonsense. INTO clause should to contains only plpgsql variables - in 9.x
Postgres there is not possible issue.
postgres=# create table x(a int, b int);
CREATE TABLE
postgres=# insert into x values(10,20);
INSERT 0 1
postgres=# create or replace function foo(out a int, out b int)
postgres-# returns record as $$
postgres$# begin
postgres$# select x.a, x.b from x into a, b;
postgres$# return;
postgres$# end;
postgres$# $$ language plpgsql;
CREATE FUNCTION
postgres=# select * from foo();
a | b
----+----
10 | 20
(1 row)

you can see, there is not any collision
Assertions

-1 to proposed syntax - I wrote about my reasons in other thread.

Regards

Pavel

>
> .marko
>