On 24.07.23 12:32, Alvaro Herrera wrote:
However, 11.16 (<drop column not null clause> as part of 11.12 <alter
column definition>), says that DROP NOT NULL causes the indication of
the column as NOT NULL to be removed. This, to me, says that if you do
have multiple such constraints, you'd better remove them all with that
command. All in all, I lean towards allowing just one as best as we
can.
Another clue is in 11.15 <set column not null clause>, which says
1) Let C be the column identified by the <column name> CN in the
containing <alter column definition>. If the column descriptor of C
does not contain an indication that C is defined as NOT NULL, then:
[do things]
Otherwise it does nothing. So there can only be one such constraint per
table.
