"Martin T." <0xCDCDCDCD_at_gmx.at> schreef in bericht
news:46cd966d$0$1347$834e42db_at_reader.greatnowhere.com...
> William Robertson wrote:
>> On Aug 22, 7:22 pm, "Paul Linehan" <plinehan__A_at_T__yahoo__D.OT__COM>
>> wrote:
>>> Mark D Powell wrote:
>>>> I have always had difficulty with the concept that an empty string
>>>> should not be considered a NULL value to begin with. What does an
>>>> empty string hold?
>>> Take an ex-girlfriend of mine, she had a child in the States
>>> and *_specifically_* didn't give her (the child) a middle name.
>>>
>>> So, Middle_Initial is blank '' - and not NULL, since it is a
>>> known quantity - as Donald Rumsfeld might say, a "known unknown".
>>>
>>> NULLs are unknown unknowns. Despite Mr. Rumsfeld's verbal
>>> gymnastics, there is no such thing as an unknown known.
>>>
>>> You concatenate blank with a string, and you simply get the string
>>> back - do the same with NULL and you get NULL.
>>>
>>> I'd say NULLs are readily distinguishable from blank strings.
>>>
>>> Paul...
>>
>> (...)
>>
>> Oracle treats nulls as empty strings when concatenating, often leading
>> to cries of inconsistency in this sort of debate, but it is the
>> overwhelmingly more useful behaviour.
>>
>
> Yeah. And Length('') == NULL which is bloody awful.
> Imho, Oracle just messed up on varchar2 and NULL. (from a practical, not a
> philosophical point of view)
>
> br,
> Martin
Much ado about nothing (or null or '' or "").
Even worse: in Dutch 0 (zero) is called "nul" and pronounced (almost) like
null.....
Shakespeare
Received on Thu Aug 23 2007 - 11:31:52 CDT
