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Table with one row

From: <zeldorblat_at_gmail.com>
Date: 19 Oct 2005 08:07:17 -0700
Message-ID: <1129734437.042073.223980_at_f14g2000cwb.googlegroups.com> 





In our system we have a table with one row ("today") that is used
solely to tell the application what the current processing date is (as
well as yesterday and tomorrow).  The table looks like this:



create table today (

        yesterday smalldatetime not null,
        today smalldatetime not null,
        tomorrow smalldatetime not null,

        check ((yesterday < today) and (today < tomorrow))


)



Since the table only has one row, we purposely join to it without a
condition (cartesian join), knowing that we won't get any more rows
than we expect.  The table is updated daily by one of our batch jobs.



My question is twofold.  First, how does one restrict the number of
rows in a table (in this case, to guarantee there's only one row) ? I
suppose you can use a trigger, but perhaps there's a better way.



Second, to be relationally correct, the table needs a primary key.
What might the key be in this situation?  It seems silly to add an
identity column since
Received on Wed Oct 19 2005 - 17:07:17 CEST












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