Re: [pgsql-general] Daily digest v1.9081 (14 messages)

Started by Oliver Kohll - Mailing Listsalmost 17 years ago2 messagesgeneral
Jump to latest
#1Oliver Kohll - Mailing Lists
oliver.lists@gtwm.co.uk

On 8 Jun 2009, at 17:23, Merlin Moncure <mmoncure@gmail.com> wrote:

Is there a way when creating a table to limit it to one row? That
is,
without using a stored procedure?

I searched the documentation, but didn't find anything.

CREATE TABLE x (...);

CREATE UNIQUE INDEX x_only_one_row ON ((1));

very clever :D

merlin

To clever for me, I don't understand what's going on and can't
replicate it in my 8.3. Any expansion?

Rgs
Oliver

oliver@gtwm.co.uk / 0845 456 1810 / 07814 828608
www.gtwm.co.uk - company
www.gtportalbase.com - product

#2David Fetter
david@fetter.org
In reply to: Oliver Kohll - Mailing Lists (#1)

On Mon, Jun 08, 2009 at 08:08:02PM +0100, Oliver Kohll - Mailing Lists wrote:

On 8 Jun 2009, at 17:23, Merlin Moncure <mmoncure@gmail.com> wrote:

Is there a way when creating a table to limit it to one row? That
is,
without using a stored procedure?

I searched the documentation, but didn't find anything.

CREATE TABLE x (...);

CREATE UNIQUE INDEX x_only_one_row ON ((1));

very clever :D

merlin

To clever for me, I don't understand what's going on and can't
replicate it in my 8.3. Any expansion?

This should actually read:

CREATE UNIQUE INDEX x_only_one_row ON x((1));

This creates a unique expressional index on the table. This
expression evaluates as true only in cases where the table has at most
one row, independently of what the possible row contains.

Cheers,
David.
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate