Mario Splivalo <mario(dot)splivalo(at)mobart(dot)hr> writes:
> I can create a FK on a column wich allows NULL values, and I can even
> insert rows with NULLs in FK column, although PK table where FK is
> pointing does not allow nuls. Is that 'by design', or...?
It's per SQL spec. Add a NOT NULL constraint to the column if you do
not wish to allow NULLs.
regards, tom lane