> Double-yikes. There goes that idea, or does it? Attributes are
> numbered. How does a missing attribute get handled for new rows?
> My guess is that we have to keep this thing around forever. Can you
> imagine having all those user apps tha query pg_attribute supress that
> column. Sound like too much work to me.
I don't know the intimate details of the postgres implementation, but I
would have thought every row would need a version number and you would
need to somehow store how the table looked at each version.
Because you could
CREATE TABLE
INSERT
ALTER DROP
INSERT/DELETE
ALTER DROP/ADD
INSERT/DELETE
and you would end up with rows with 5 or 6 different formats.