On Fri, 20 Dec 2013 14:15:38 +0100, Fulvio Senore <[email protected]> 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
