Обсуждение: predefined functions

Hi,

Is there a reason why both:

    SELECT current_user;
    SELECT current_database();

are correct, while neither of:

    SELECT current_user();    -- syntax at '('
    SELECT current_database; -- missing column

is?

This is as of postgres version 8.1.4

--
Rafal Pietrak <rafal@poczta.homelinux.com>

Rafal Pietrak <rafal@poczta.homelinux.com> writes:
> Is there a reason why both:
>     SELECT current_user;
>     SELECT current_database();
> are correct, while neither of:
>     SELECT current_user();    -- syntax at '('
>     SELECT current_database; -- missing column
> is?

Yeah: current_user (without the parens) is specified by the SQL
standard, but we're not about to adopt such a brain-dead syntax
for any of the functions defined by Postgres itself --- as you
can see from the error messages, allowing a function to be called
without parens creates a word that can't be used as a column name.
So if current_database could be called without parens, we'd actually
be violating the SQL spec by reserving a word that's not reserved
per spec.

Consistency is not one of the hallmarks of the SQL standard :-(

            regards, tom lane

On Sun, 2006-10-08 at 01:44 -0400, Tom Lane wrote:
> Yeah: current_user (without the parens) is specified by the SQL
> standard, but we're not about to adopt such a brain-dead syntax
> for any of the functions defined by Postgres itself --- as you

I see. One of "committee's work gems" :(

And yet, does that really imply faulting syntax on "current_user()"?


--
-R