[freetds] empty strings select as null bug

Jeffrey Shaw shawjef3 at gmail.com
Thu Jun 11 10:11:02 EDT 2015


Hi Geoff,
Confirmed! My test for the bug now passes.

Jeff

On Thu, Jun 11, 2015 at 3:17 AM, Geoff Montee <geoff.montee at gmail.com>
wrote:

> On Wed, Jun 10, 2015 at 10:39 PM, LacaK <lacak at zoznam.sk> wrote:
> >
> > I am using for testing NULL dbdata(), which should return nil for NULL
> data.
> > (In my case I know, that column exists)
> >
> > From Sybase documentation:
> > "A NULL BYTE pointer is returned if there is no such column or if the
> data
> > has a null value. To make sure that the data is really a null value, you
> > should always check for a return of 0 from *dbdatlen*."
> >
> > From Microsoft documentation:
> > "A NULL BYTE pointer is returned if there is no such column or if the
> data
> > has a null value. To make sure that the data is really a null value,
> check
> > for a return of 0 from *dbdatlen*."
> >
> > So you can use: dbdata()==nil && dbdatlen()==0
> >
>
> I decided to go with your test:
>
>
> https://github.com/GeoffMontee/tds_fdw/blob/b5f678cded099f9231473c520cf1dbe8363a470a/src/tds_fdw.c#L1855
>
> I think Jeff's bug is fixed.
>
> It's really good to know that dbdatlen() can return 0 in the case of
> an empty string.
>
> Thanks for your help, everyone!
>
> Geoff
> _______________________________________________
> FreeTDS mailing list
> FreeTDS at lists.ibiblio.org
> http://lists.ibiblio.org/mailman/listinfo/freetds
>


More information about the FreeTDS mailing list