Re: plpgsql - DECLARE - cannot to use %TYPE or %ROWTYPE for composite types

2016-01-18 22:48 GMT+01:00 Robert Haas <robertmhaas(at)gmail(dot)com>:

> On Mon, Jan 18, 2016 at 4:35 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> >> I know that Oracle uses syntax of this general type, but I've always
> >> found it ugly. It's also pretty non-extensible. You could want
> >> similar things for range types and any other container types we might
> >> get in the future, but clearly adding new reserved words for each one
> >> is no good.
> >
> > It doesn't use reserved worlds.
>
> OK - keywords, then.
>
> >> One idea that occurs to me is: If you can DECLARE BAR FOO%TYPE, but
> >> then you want to make BAR an array of that type rather than a scalar,
> >> why not write that as DECLARE BAR FOO%TYPE[]? That seems quite
> >> natural to me.
> >
> > what you propose for syntax for taking a element of array?
>
> No idea.
>

the syntax for "array from" is natural, but for any other is hard. So it is
reason, why I used text form. Using Oracle's pattern source%operation
allows to use nonreserved keywords. Probably any text can be there. The
keywords isn't necessary (not tested).

> >> I think the part of this patch that makes %TYPE work for more kinds of
> >> types is probably a good idea, although I haven't carefully studied
> >> exactly what it does.
> >
> >
> > I invite any ideas, but currently used notation is only in direction
> > type->array. The working with symbols looks more difficult, than using
> words
> > (in design area).
> >
> > More - the textual form is more near to our system of polymorphics types:
> > anyelement, anyarray, ... We have not anyelement[]
>
> True, but this is hardly a straightforward extension of what we have
> today either.
>

It is, but sometime the polymorphic types can help.

The proposed feature/syntax has sense primary for polymorphic types. It
should to follow our polymorphic types. The primary pair is
"anyarray","anyelement" -> "arraytype","elemementtype".

If you don't use polymorphic parameters in plpgsql, then proposed feature
can look like useless.
Regards

Pavel

>
> --
> Robert Haas
> EnterpriseDB: http://www.enterprisedb.com
> The Enterprise PostgreSQL Company
>