On 14 Jun 2005, at 17:52, [EMAIL PROTECTED] wrote:
My suggestion, lame as it is, would be to use a 0 (zero) in place
of the
NULL value. That way, you always have a valid entry for PARENT_ID,
you can
still identify the tops of the trees (parent_id=0) and you have gotten
around the only-one-pa
Marcus Bointon <[EMAIL PROTECTED]> wrote on 06/14/2005 12:37:18
PM:
> I have a table that uses a self join to represent simple hierarchies.
> I have a parent_id field that contains a reference to the same
> table's id field. Not all items have a parent, so parent_id is nullable.
> The problem I
In some hierarchies I have seen people put the the current id in the
parent_ID Field {basicaly pointing to them self} to represent the top of
the hierarchy.
I don't know how much this would affect the rest of your application but
it would get rid of the null's
-Original Message-
From: Ma
On Saturday 15 March 2003 04:08, vishnu mahendra wrote:
> create table stud(rno integer not null,
> name char(10),
> primary key(rno));
>
> create table mark(rno integer not null references
> stud,
> mark integer);
[skip]
> how is it possible.
> there is no rollno 3 in the stud table,
> then how
