Re: FW: Informix versus Oracle Spatial

Just tryed:

create table nullix( a int, b char(10), primary key(a));

insert into nullix (b) values ('One ');

• error does not allow null in col a ...

So obstacle is dictating to have a PK which does not allow nulls in my table...

this:
create table nullix( a int unique , b char(10));

insert into nullix  (b) values ('One ');
insert into nullix  (b) values ('One Dupl');
insert into nullix  (b) values ('Two Dupl');

succeeds....

> Absolutely. null is absence of any information about a datum,
> how can you know that it is a duplicate? It might well not be.

sorry mate i disagree with you on that

select * from nullix where a is null

gives me the info.

so sqlnul is sqlnul and also sqlnull in an index and is a unique value;

to get the real answer i guess one has to goto the sql specs. -- haven't got them; any takers....???

Superboer.

Noons schreef:

> rkusenet apparently said,on my timestamp of 1/12/2005 10:11 PM:
>
> > my knowledge about Oracle is minimal.
> >
> > Could it be because Oracle does not index null values.
>
> Actually, it can. Quite easily. But it requires reading
> a manual, something these "geniuses" are alergic to...
>
>
> >>
> >>you will probably tell me that the above is how it should work...
> >>right??
> >>having multiple null values in a unique index....
> >>
>
> Absolutely. null is absence of any information about a datum,
> how can you know that it is a duplicate? It might well not be.
>
> You are confusing unique index with primary key index and
> unique key. There is a difference. Unnoticed in products that
> don't have a clue what keys are for. But once again, it requires
> reading a manual...
>
> --
> Cheers
> Nuno Souto
> in stormy Sydney, Australia
> wizofoz2k_at_yahoo.com.au.nospam
Received on Fri Dec 02 2005 - 08:07:11 CST