Posted by Erland Sommarskog on 01/15/07 22:44

(markjerz@googlemail.com) writes:
> Now, table2 has a rule on various columns:
>
> @CHARACTER IN ('Y','N')
>
> but the column allows nulls, in the design view is says so anyway.
>
> When I run this query I get:
>
> A column insert or update conflicts with a rule imposed by a previous
> CREATE RULE statement. The statement was terminated. The conflict
> occurred in database 'database', table 'table', column 'column'.
> The statement has been terminated.
>
> Obviously, I've changed the names of everything.
>
> The only data in those columns which could possibly conflict with the
> rule is the NULL value. Any ideas why this doesn't work?

In my opinion it is a bug, but it has been way since SQL 7 (SQL 6.5
did it right), and Microsoft considers rules to be a deprecated feature,
so I have no hope for a fix.

The workaround is to write the rule so that it explicitly permits NULL.

As for the deprecation - binding rules directly to table columns is a poor
idea; use constraints instead. However, in my opinion Microsoft has
failed to understand that binding rules to user-defined types is an
asset, and for which they do not have any replacement.

--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx

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