Thread: SPI_fnumber can't see oid

It seems SPI_fnumber can't recognize oid as an attribute for a tuple
description. I performed my tests using contrib/spi/refint.c which uses
function to test the validity of the trigger for check_foreign_key() and
for check_primary_key(). I changed refint.c slightly to verify that
SPI_fnumber was really returning SPI_ERROR_NOATTRIBUTE and indeed it was.
Here's the exact line I got from the check_foreign_key trigger:

ERROR: check_foreign_key: there is no attribute oid in relation product

Looking at src/backend/executor/spi.c, I noticed SPI_fnumber started
counting at 0. Is this normal or should it be -1, assuming oid might be
just before 0?

Let me know what you think,
Marc

admin <admin@wtbwts.com> writes:
> ERROR: check_foreign_key: there is no attribute oid in relation product

> Looking at src/backend/executor/spi.c, I noticed SPI_fnumber started
> counting at 0. Is this normal or should it be -1, assuming oid might be
> just before 0?

I think the SPI code is deliberately set up to prevent access to
the system attributes.  Jan Wieck is probably the only one who knows
exactly why, but I'll bet that something will break if you bypass
that restriction :-(
        regards, tom lane