Re: GSoC 2017: Foreign Key Arrays

On Thu, Jul 27, 2017 at 3:07 PM, Mark Rofail <markm(dot)rofail(at)gmail(dot)com> wrote:

> On Thu, Jul 27, 2017 at 12:54 PM, Alexander Korotkov <aekorotkov(at)gmail(dot)com
> > wrote:
>>
>> How many rows of FK table were referencing the PK table row you're
>> updating/deleting.
>> I wonder how may RI trigger work so fast if it has to do some job besides
>> index search with no results?
>>
> The problem here is that the only to option for the foreign key arrays are
> NO ACTION and RESTRICT which don't allow me to update/delete a refrenced
> row in the PK Table. the EXPLAIN ANALYZE only tells me that this violates
> the FK constraint.
>
> So we have two options. Either implement CASCADE or if there's a
> configration for EXPLAIN to show costs even if it violates the FK
> constraints.
>

Oh, ok. I missed that.
Could you remind me why don't we have DELETE CASCADE? I understand that
UPDATE CASCADE is problematic because it's unclear which way should we
delete elements from array. But what about DELETE CASCADE?

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company