Re: Proposal: variant of regclass - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: Proposal: variant of regclass
Date
Msg-id CAFj8pRAMJ1b6vjxsp-76CjOtiKBxTPxuMW6gnMqCLcDCWg1K5Q@mail.gmail.com
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In response to Re: Proposal: variant of regclass  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: Proposal: variant of regclass
List pgsql-hackers



2013/12/5 Andres Freund <andres@2ndquadrant.com>
On 2013-12-04 20:25:53 -0500, Tom Lane wrote:
> Tatsuo Ishii <ishii@sraoss.co.jp> writes:
> > I would like to add a variant of regclass, which is exactly same as
> > current regclass except it does not raise an error when the target
> > table is not found. Instead it returns InvalidOid (0).
>
> I've sometimes thought we should just make all the reg* input converters
> act that way.  It's not terribly consistent that they'll happily take
> numeric inputs that don't correspond to any existing OID.  And more
> often than not, I've found the throw-an-error behavior to be annoying
> not helpful.

I find that to be a bit of a scary change. I have seen application check
for the existance of tables using the error thrown by ::regclass. Now,
they could change that to check for IS NULL which would be better for
them performancewise, but the likelihood they will notice in time seems
small.


this change can break some applications

but personally I like this change.

We can introduce some assert polymorphic function

CREATE OR REPLACE FUNCTION notnull(any, message text) RETURNS any, that can be used for check inside SQL

Regards

Pavel
 
Greetings,

Andres Freund

--
 Andres Freund                     http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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