Re: Oracle NULL vs '' revisited

From: Shakespeare <whatsin_at_xs4all.nl>
Date: Tue, 21 Aug 2007 10:18:33 +0200
Message-ID: <46ca9fe8$0$234$e4fe514c@news.xs4all.nl>

"Ed Prochak" <edprochak_at_gmail.com> schreef in bericht news:1187663153.833953.174740_at_57g2000hsv.googlegroups.com...

> On Aug 17, 2:44 pm, "David Portas"
> <REMOVE_BEFORE_REPLYING_dpor..._at_acm.org> wrote:

>> "Thomas Kellerer" <FJIFALSDG..._at_spammotel.com> wrote in message
>>
>> news:5im5abF3p468kU1_at_mid.individual.net...
>>
>>
>>
>> >> I don't think that there is a similar "empty" concept for dates.
>> > That's my point. Character seems to be the only data were everybody
>> > requires the distinction between "nothing" and "empty" but nobody has
>> > ever
>> > requested this distinction for dates or numbers.
>>
>> The question of whether we choose to refer to some value as "empty" is
>> entirely beside the point in my opinion. The issue is that the domain of
>> string values supported by Oracle is not equivalent to the domain of
>> string
>> values supported by any other DBMS or programming language that I know
>> of.
>> Null is not a value. A string consisting of zero characters IS a value
>> anywhere except Oracle.

>
> Oracle is not the only DBMS with this characteristic.
> UNIFY DataServer has the same "feature".
>
> I don't  agree that a string consisting of zero characters IS a value.
>
> Is "" logically different from " "? If I have a user filling out an on-
> line form and they enter nothing into one of the fields, I would load
> a NULL in the DB. Would you really try loading an empty string? What
> would that mean exactly??
>

>>
>> You could "design out" the problem as Daniel Morgan suggests but then you
>> may have to accept that some process or function which potentially has to
>> support zero-length string values can no longer use Oracle as a data
>> store.

>
> Only if "" carries some meaning. I for one don't think it has any
> meaning outside a C program (where it is a one byte array initialized
> with a zero byte value). If you really want "" then you likely want a
> BLOB column.
>

>> Alternatively, you have to compromise by using nulls to represent values
>> or
>> converting the strings to some other data type or representation.
>>
>> --
>> David Portas

>
> The compromises only are needed if you embue "" with some meaning.
> Otherwise, life is good.
>
> ed
>
>

And even if "" had some meaning, life could still be good....

Shakespeare Received on Tue Aug 21 2007 - 03:18:33 CDT