On Thu, Jun 4, 2009 at 1:23 PM, Brandon Metcalf
<brandon@geronimoalloys.com> wrote:
> Got it. Currently, it doesn't have a column for an ID, but I can add
> one if this is the only way.
Actually any column with a unique index on it will work. It doesn't
have to be primary key or even a serial id.
ANSI-SQL 92 allows for the following syntax:
CONSTRAINT Only_one_row
CHECK( 1 >= (SELECT COUNT(*) FROM _this_table;));
However, I have yet to find a RDBMS (PostgreSQL included) that
supports select statements in a table's check constraint.
--
Regards,
Richard Broersma Jr.
Visit the Los Angeles PostgreSQL Users Group (LAPUG)
http://pugs.postgresql.org/lapug