Re: SQLLDR and existing records/Unique constraint which allow nulls?

U¿ytkownik "Major" <lievonen_at_jyu.fi.HALOOOOOOOO> napisa³ w wiadomo¶ci news:Eb1j7.118$3h3.4423_at_read2.inet.fi...
> Hello.
>
> I have table which have primary key (sequence).
>
> I have one varchar2 field in source file and table,
> whose should be "unique".
> So when I uploadin to database, I should check
> that is this value in the table and if not, load it and
> if it is in table, skip record.
> How I can do this?

Do nothing, if record violate unique constraint rule then sql*loader doesn't [Quoted] load it and will put in into *.bad file.

> I think so that I cannot define unique constraint to table because
> this field can have null -value (source files haven´t null values).
> Is this true that unique constraint doen't allow null values?

Unique constraint allows nulls, only if column isn't defined as NOT NULL. Unique constraint + not null constraint = PRIMARY KEY constraint :)

> Is there any other constraits which is like unique but allow nulls?

No.

IF i'm wrong correct me please.

/Noel Received on Wed Aug 29 2001 - 12:00:26 CEST