"Christopher Kings-Lynne" <chriskl@familyhealth.com.au> writes:
>> Yes, I know. I mean how does this affect performance? How this can change
>> planner decision? Does it have any effect except cosmetical one?
> Only cosmetic. In the example he gave, he wanted a primary key, so I showed
> him how to make one properly.
The ALTER form will complain if any of the columns are not marked NOT
NULL, so the difference isn't completely cosmetic.
regards, tom lane