Re: Oracle NULL vs '' revisited

On Aug 17, 2:44 pm, "David Portas"
<REMOVE_BEFORE_REPLYING_dpor...@xxxxxxx> wrote:
"Thomas Kellerer" <FJIFALSDG...@xxxxxxxxxxxxx> wrote in message

news:5im5abF3p468kU1@xxxxxxxxxxxxxxxxxxxxx



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


.

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