Originally posted by abhaysk
Jurij,

I am not sure if you have seen the DEFFERED column i posted, but let me post it again.
Oh yes, I have seen it, it said IMMEDIATE. However you have not posted the DEFERRABLE column in your first post as you did now. So I had every reason to belive your PK was deferrable.

Well, PK constraint being defined as deferrable is my only explanation about PK columns not having NOT NULL constraint.