AW: Creating SQL Index

["Birgitta Hauser" <Hauser@xxxxxxxxxxxxxxx>]

> > Doesn't the "where rrn(a") preclude the use of an index, always causing a
table scan?  

Using RRN(x) in the where condition will cause either a table scan or a
table probe (if there are no other where conditions).
In this way updating multiple records within a table based on the relative
record no will cause the table to be (completely) read multiple times.

> > Or did something change on a recent release?
No, even with the enhancements in release 6.1 which allows you to create
derived or sparse indexes, it is not possible to build an index over a
relative record no.

Mit freundlichen Grüßen / Best regards

Birgitta Hauser

"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them
and keeping them!"


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Von: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] Im Auftrag von
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Gesendet: Wednesday, 23. June 2010 03:04
An: midrange-l@xxxxxxxxxxxx
Betreff: Re: Creating SQL Index

Ummm.  
Or did something change on a recent release?

Sam

On 6/22/2010 4:19 PM, Kurt Anderson wrote:
> I have a procedure in a service program that I'd like to change to use
SQL, but I can't seem to get my finger on how the index should look so the
optimizer picks it up.  Here is the SQL in the procedure.  The select is
actually a part of a declare.  I'm fetching 250 rows at a time, and updating
every row.
>              Select Cust#, CalDte, Pac#, Dept#, CalTyp, DstFlg, BAmt,
DspQty,
>                     Loc#, PrtFlg, SvPrtFlg, RRN(a)
>                From CdrMstP a
>               Where Cust# = :Cust# and CalDte<= :CutOff
>                 and StmDte = '0001-01-01'
>            Order By Cust#, CalDte;
>
>             Update CdrMstP a
>             Set StmDte = :StmtDate,
>                 Corp# = :Corp#,
>                 Loc# = :ds_CdrOut.Loc#,
>                 Dept# = :ds_CdrOut.Dept#,
>                 PrtFlg = :ds_CdrOut.PrtFlg,
>                 SvPrtFlg = :ds_CdrOut.SvPrtFlg
>             where rrn(a) = :ds_CDROut.CdrRRN;