On Aug 17, 10:49 am, Matthew Harrison <m.harris...@craznar.com> 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?   Oh wait, there is a binary zero used to indicate
that the last user data value preceeds the binary zero.  And if you
compare two binary zeroes you get an equality so two empty strings are
considered equal, but logically if the value is unknown there is no
way determine if A = b, A < B, or A > B.

The string construct was a way for the developers of C to deal with
the fact the processor they were using did not have instructions that
delt with character data very well.  Now we are apparently stuck with
it.

For the most part when dealing with character data that could be
unknown I have not found NULLs to be a problem even when the null had
to be transferred into a string variable in a program.  The database
behaves by one set of rules and the program by another.  If you need
to treat nulls in a specific column as equal (emtpy strings) then you
can use the NVL function in your where clause conditions, the is null
and is not null conditions, and/or an additional attribute column to
indicate empty where the column could also be NULL to handle the
situation.

IMHO -- Mark D Powell --