Re: PL/PgSQL discussion

Jan Wieck wrote:

> > >     Hmmm  -  how  does  a language handler then notice that a new
> > >     session began?
> >
> > Probably by defining the reset_session or init_session functions for the language handler and
> > calling it at the connect time.
>
>     Not in the current implementation of the backend/pl_handler
>     interface. But a global variable SessionId might help.

Neither do we have backend pooling now.

> > > > Then we would not need the END IF, END LOOP etc.
> > >
> > >     The LOOP ... END LOOP etc. syntax  is  just  what  I  saw  in
> > >     Oracles   PL/SQL   documentation.  I  could  also  live  with
> > >     BEGIN...END, but what is it good for to be different?
> >
> > then again we don't need the block delimiters ;)
>
>     Forgotten  in  the  1st  draft.  Variables are initialized to
>     their default values every time a block/subblock is  entered.
>     Not only when the function is entered.
>
>       ...
>       FOR i IN 1..10 LOOP
>         DECLARE
>           flag bool DEFAULT false;
>           n integer DEFAULT 0;
>         BEGIN
>         ...
>         END;
>       END LOOP;
>       ...

Ok, this makes sense.

> > This again can be done by automatically rewriting these to additional statements to check for
> > this as first things in the function body. It makes only a theoretical difference if the error
> > is reportid before the call or just after it.
>
>     But this rewriting must be done when the function is created.
>     At this time, the pl_handler and it's parser  aren't  called.

Ok, I understand it now.

<name> ALIAS FOR $n;

is to overcome the split between the two parser.

>     It  is  done  by  the  backends  main  parser.  For  loadable
>     procedural languages, the main parser doesn't  know  anything
>     about the languages syntax or if the string given after AS is
>     a program text at all. It only creates the pg_proc tuple.

And another thing:

Does'nt the Oracle PL/SQL have both input and input/output parameters ?

It's more than a year since i last used it but I think that this is the case.

Hannu