r == richard.broersma@gmail.com writes:
r> On Thu, Jun 4, 2009 at 1:23 PM, Brandon Metcalf
r> <brandon@geronimoalloys.com> wrote:
r> > Got it. �Currently, it doesn't have a column for an ID, but I can add
r> > one if this is the only way.
r> Actually any column with a unique index on it will work. It doesn't
r> have to be primary key or even a serial id.
r> ANSI-SQL 92 allows for the following syntax:
r> CONSTRAINT Only_one_row
r> CHECK( 1 >= (SELECT COUNT(*) FROM _this_table;));
r> However, I have yet to find a RDBMS (PostgreSQL included) that
r> supports select statements in a table's check constraint.
I had thought about a subquery in the constraint, but as you say, that
didn't work.
Thanks for the help.
--
Brandon