Re: Resource for index

Dear Stephane,

At first, my apologize by the word "Resource", it was the first word that I found out and wrote it.

The case is that this command +0 , you can put it in the sentence line of where and the sintaxe is correct.
Oracle executes the statment and don't gives error message.

My doubt is : What this +0 does in the sql ? Imagine a column unindexed that you can not create a index, because it will do a bad performance in all the system, you can use +0 that it will break the index . It is what i eard.
But i am searching about this +0 and until now, i didn't find out nothing about it.
For me it doesn't exist.

Did you do a test ?
You can put it at the statment that will run , normaly.

And more, if you to use explain plan the table (unindexed) will have a FULL TABLE SCAN. So, I ask :
What is this +0 ? Resource or not , it is my hard doubt.

Regards
Eriovaldo

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Monday, October 13, 2003 4:04 PM

> > Friends :
> >
> > I have a part of statment as below :
> >
> > select column1 from table1
> > where column1 = v_parameter;
> >
> > The column1 is not indexed, so the table full scan will be executed.
> > Right?
> > Well, I would like to know if anyone knows the resource :
> >
> > select column1 from table1
> > where column1 = v_parameter +0
> >
> > What does it mean (+0).
> > What kind of resource is it ?
> > What does it do ?
> >
> > Best Regards
> >
> > Eriovaldo
>
> Eriovaldo,
>
> Don't understand too well what you mean by 'resource'. One of the
> most cunning performance tips of yore was to either concatenate an empty
> string to a string or date column or add a zero to a number column to
> prevent the RBO from using an index on this column (BTW it's a trick
> which can still be useful at times) when this index was known to be not
> very selective.
> Quite obviously, applying this to the constant part of an equality is
> totally pointless. And since the column is unindexed, it wouldn't have
> much utility either on the other side of the equality.
> Another case of ill-digested and ill-understood trick.
>
> --
> Regards,
>
> Stephane Faroult
> Oriole Software
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Stephane Faroult
> INET: sfaroult_at_oriole.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Eriovaldo Andrietta
  INET: eca_at_siteplanet.com.br

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