Re: Oracle 7.1 Enhancements

In article <CrCuMK.EpC_at_gremlin.nrtc.northrop.com> msallwas_at_world.nad.northrop.com (Michael Sallwasser) writes:
> In article <Cr3p9s.D9_at_freenet.carleton.ca> ah513_at_FreeNet.Carleton.CA
 (Doug Harris) writes:
> >
> >
> >In a previous article, jdennis_at_netcom.com (John Dennis) says:
> >>
> > I would also like to know if 7.1 can distinguish between empty
> >CHAR/VARCHAR values (i.e. '') and NULL.
> >
>
> Please explain. NULL and empty values are conceptually the same thing.

No! Read Codd, who defined what key points a relational database should have and one thing that he clearly states is that NULL has to be different from anything else. NULL denotes a missing value (unknown), whereas a empty string is a string. E.g. a telephone number: NULL means unknown (no information), empty means the guy has none (information).

> Are you experiencing differences in behaviour between statements such
> as these two:

Of course!

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