Re: Problem merging two rows into same primary key

Hi and thanks for your reply!

Martijn van Oosterhout wrote:
>>Now to the problem. We want to merge rows with id = 2 and id = 4 into id
>>= 1 in the asdf table with the qwert table beeing updated to reflect the
>>change. The desired result would yeild:
>
>
> Why doesn't:
>
> update quert set data = 1 where data = 2;
> update quert set data = 1 where data = 4;
> delete from asdf where id in (2,4);
>
> work?
>
> I thought update cascade only took effect when the primary key changed,
> it updated referencing tables, not the other way round.

Sure it will work, but it's quite a bit of work since there are a LOT of
tables that need to be updated. We were hoping there was an easier way
and before we actually took a look at how things work we were hoping
it'd be possible to somehow take advantage of the "on update cascade" of
the foreign keys by first droping uniqueness from primary key index. But
the more I think about it the more impossible it seems. :(

Oh, well... I guess we'll go with the massive update route.

Thanks,
Patrik