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

Hi

2016-02-24 22:18 GMT+01:00 Peter Eisentraut <peter_e(at)gmx(dot)net>:

> On 1/18/16 4:21 PM, Robert Haas wrote:
> > 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.
>
> Right, and it's arguably dubious that that doesn't already work.
> Unfortunately, these % things are just random plpgsql parser hacks, not
> real types. Maybe this should be done in the main PostgreSQL parser
> with parameter hooks, if we wanted this feature to be available outside
> plpgsql as well.
>

I am not fan to propagate this feature outside PLpgSQL - it is possible new
dependency between database object, and the cost is higher than benefits.

>
> > 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 agree that this should be more general. For instance, this patch
> would allow you to get the element type of an array-typed variable, but
> there is no way to get the element type of just another type. If we
> could do something like
>
> DECLARE
> var ELEMENT OF point;
>

isn't it bug? What is sense of this construct? Our other manipulation with
a arrays we raise a error, when we try to to take a element from non array
value.

Today I did work on this patch and I am able to implement the syntax
proposed by you. It is proprietary, but similar to ADA anonymous types.

DECLARE x array() of type

Regards

Pavel

>
> (not necessary that syntax)
>
> then
>
> DECLARE
> var ELEMENT OF othervar%TYPE;
>
> should just fall into place.
>
>