Re: Prevent ALTER TABLE DROP NOT NULL on child tables if parent column has it

On 6/15/16, Michael Paquier <michael(dot)paquier(at)gmail(dot)com> wrote:
> On Thu, Jun 16, 2016 at 12:10 PM, Vitaly Burovoy
> <vitaly(dot)burovoy(at)gmail(dot)com> wrote:
>> In the initial letter[1] I posted a digest from the SQL-2011 standard
>> and a conclusion as a design of a new patch.
>> Now I have more free time and I'm hacking it that way. The new patch
>> is at the very early stage, full of WIPs and TODOs. I hope it'll be
>> ready to be shown in a month (may be two).
>
> I have just read both your patch and the one of Alvaro, but yours does
> not touch pg_constraint in any way. Isn't that unexpected?

The consensus was reached to use CHECK constraints instead of new type
of constrains.
Alvaro made attempt[1] to write PoC in 2012 but it failed to apply on
top of master (and after solving conflicts led to core dumps) in Jan
2016.

I just rebased Alvaro's one to understand how he wanted to solve issue
and to run tests and queries. After all I sent rebased working patch
for anyone who wants to read it and try it without core dumps.

I have not published my patch for NOT NULLs yet.

Alvaro, the correct path[2] in the second message[3] of the thread.
What's wrong in it (I got the source in the previous[1] thread)?

[1] https://www.postgresql.org/message-id/flat/1343682669-sup-2532(at)alvh(dot)no-ip(dot)org
[2] https://www.postgresql.org/message-id/attachment/41886/catalog-notnull-2-c477e84_cleaned.patch
[3] https://www.postgresql.org/message-id/CAKOSWNnXbOY4pEiwN9wePOx8J%2BB44yTj40BQ8RVo-eWkdiGDFQ%40mail.gmail.com
--
Best regards,
Vitaly Burovoy