I was trying to update attnotnull = 't' in the pg_attribute to add Not Null
constraint to a table. It gave me a Permission denied.
Is this standard? Am I not allowed to change system catalogues (I am using
the postgres superuser!) I thought I had heard this would work. Or can you
only change attnotnull to false i.e. remove a not null constraint? I
suppose this would make some kind of sense, as there could already be Nulls
in the field.
Thanks in advance
Ben
