Re: [HACKERS] proposal: schema variables

2018-04-20 17:32 GMT+02:00 Robert Haas <robertmhaas(at)gmail(dot)com>:

> On Tue, Apr 17, 2018 at 12:28 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> > It true, so there are lot of "unused" attributes for this purpose, but
> there
> > is lot of shared attributes, and lot of shared code. Semantically, I see
> > variables in family of sequences, tables, indexes, views. Now, it shares
> > code, and I hope in next steps more code can be shared - constraints,
> > triggers.
>
> I dunno, it seems awfully different to me. There's only one "column",
> right? What code is really shared here? Are constraints and triggers
> even desirable feature for variables? What would be the use case?
>

The schema variable can hold composite value. The patch allows to use any
composite type or adhoc composite values

DECLARE x AS compositetype;
DECLARE x AS (a int, b int, c int);

Constraints are clear, no.

Triggers are strange maybe, but why not - it can be used like enhanced
constraints, can be used for some value calculations, ..

> I think stuffing this into pg_class is pretty strange.
>

It will be if variable is just scalar value without any possibilities. But
then there is only low benefit

The access rights implementation is shared with other from pg_class too.

Regards

Pavel

>
> --
> Robert Haas
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