Re: Migrating an application with Oracle temporary tables

pá 3. 5. 2019 v 8:19 odesílatel Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
napsal:

> On Thu, 2019-05-02 at 16:55 +0000, Mark Zellers wrote:
> > I thought I needed the prototype table to be able to define functions
> and procedures that refer to the temporary table but do not create it.
> >
> > Perhaps my assumption that I need the table to exist (whether as a
> temporary table or as a permanent table) in
> > order to define the function/procedure is incorrect. I'll take a look
> at that.
>
> You don't need the table to exist at function definition time.
> The following works just fine, even if the table does not exist:
>
> CREATE FUNCTION f() RETURNS void LANGUAGE plpgsql AS $$BEGIN PERFORM *
> FROM notexists; END;$$;
>
> This is because functions are not parsed when they are defined.
>

It is not fully correct - function with queries are parsed and syntax check
is done. But semantic check is deferred on run time.

Regards

Pavel

> > I did find a scenario where this approach does run into trouble. That
> is, if the function/procedure is executed
> > against the permanent table and then you go to run it against a
> temporary table. In that case, I do get the
> > wrong answer, and I haven't yet figured out how to reset that without
> dropping the procedure and re-defining it.
> > For my purposes, that is "good enough" -- I can promise not to run such
> procedures against the temporary table.
>
> Yes, that would cause a problem.
>
> The SQL statement "DISCARD PLANS" should fix the problem.
>
> Yours,
> Laurenz Albe
>
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>
>
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