On Fri, 20 Dec 2013 14:15:38 +0100, Fulvio Senore <mailing@...>
wrote:

> I have two tables, for example TableA and TableB.
>
> Each row of TableA contains a foreign key to a row of TableB.
> This a 1 to 1 relation, so each row of TableA is linked to one different

> row of TableB.
> The foreign key field can also be NULL, in this case the TableA row is
> not connected to a TableB row.
>
> All TableB rows depend logically on TableA rows, so all TableB rows
> should be linked by a TableA row.
>
> I would like to check for program errors during development, so I would
> like to know if there are "orphans" TableB rows.
>
> May somebody suggest me a good way to find the rows in TableB that are
> not connected from any row in TableA?

To me it sounds like you have the dependencies reversed: TableB should
have a foreign key to TableA, and not the other way around.

Mark