Re: AW: defining files with sql but using setll/read to access

Hi Vern and Jim,

Yeah Jim, I believe so - you don't have a subset of the fields in an

index, as you can with standard logical files.

This is true before release 6.1.

Under release 6.1 it is possible to define indexes with a field selection.
It is even possible to define additional columns, for example a column for
quantity*price or Upper(MyFld). These new columns can also be defined as key
fields.
... and even more you can specify where conditions within an index just like
select/omit clauses within logical files.
What is not possible with an index is to build an index over joined tables,
i.e. there is no replacement for keyed join logical files.

BTW currently these enhancements work with native I/0, while the SQL query
optimizer is not yet able to exploit all these enhancements.

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!"

-----Ursprüngliche Nachricht-----
Von: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] Im
Auftrag von Vern Hamberg
Gesendet: Friday, 14. August 2009 00:49
An: RPG programming on the IBM i / System i
Betreff: Re: defining files with sql but using setll/read to access

Yeah Jim, I believe so - you don't have a subset of the fields in an index, as you can with standard logical files. With a view, you'd have a subset and no key - an unkeyed logical basically.

Vern

JDHorn@xxxxxxxxxxxxxx wrote:

I think this means that -when you specify an index the compiler gets

the

physical file definition for all the fields?

Jim Horn

____________________________________________________

------------------------------

message: 7
date: Thu, 13 Aug 2009 14:00:21 -0500
from: Vern Hamberg <vhamberg@xxxxxxxxxxx>
subject: Re: defining files with sql but using setll/read to access

Just like any other PF or LF - for a table, put its name in an F-spec

-

if it has a primary key that you want to use, declare as keyed in the
usual manner.

For an index, just put its name in the F-spec and declare it keyed.

I think you can even use a view, but it has to be treated as arrival
sequence. Right, you other SQL mavens?

All is the same as you know how to do!!

HTH
Vern

JDHorn@xxxxxxxxxxxxxx wrote:
> As time goes by, I am certainly seeing the advantage of using

sql

to
> access files, especially for search and display.
>
> In an rpg program, what is a good way to use a sql defined file

for

> setll/read access?
>
> Jim Horn
>

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