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I'm with Charles on this one.

If you really want to use an SQL index as the underlying data space index
structure for benefits of larger logical page size, you can build the SQL
index and THEN build the LF that you want. Since LF will be keyed by the
keys identical to the SQL index keys, keyed LF will share the data space
index of the SQL index, so you don't have the overhead of maintaining two
binary trees.
Now you can access the LF as keyed, and LF DDS definition can restrict the
columns available to your program.

We call this technique logical file slip. Not sure who came up with it, but
it's been very useful prior to V5R4.
On V5R4, you now have the PAGESIZE keyword so you can specify 64K logical
page size if you wish to have it. Or even 512K if you're really crazy about
blocking :)

All of this discussion aside and with you being a stickler for DDL, why not
simply use embedded SQL in your RPG program instead? No need for LFs then
and you have access to that magical thing called ORDER BY :)

Elvis

RPG & DB2 Summit | Minneapolis | October 1-4
Mike Cain - DB2 for i5/OS Temporary Indexes - The Good, The Bad, The Ugly
October 16
2007 System i Fall Technical Conference | Orlando | November 4-7
Celebrating 10-Years of SQL Performance Excellence on IBM System i, eServer
iSeries and the server affectionately known as the AS/400

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Wilt, Charles
Sent: Tuesday, September 11, 2007 3:42 PM
To: Midrange Systems Technical Discussion
Subject: RE: CREATE INDEX and name only some columns

Why?

If you need it for native I/O, use a DDS logical.

As long as the physical file is defined with DDL, you get the important
benefits of using DDL vs. DDS
including:
-Validation on Write instead of Read
-64K Access paths (when logical shares an SQL access path)

As long as you're using native I/O you're _are_ going to have to have DDS
logicals. Unless you're
writing/rewriting from the ground up to avoid the need for capabilities only
available to DDS
logicals.

HTH,
Charles


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jeff Crosby
Sent: Tuesday, September 11, 2007 4:29 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: CREATE INDEX and name only some columns

Poop.

Yes I need it for native I/O. I'll figure out another way.
But I _AM_ going to define this file via DDL.

--
Jeff Crosby
UniPro FoodService/Dilgard
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531

The opinions expressed are my own and not necessarily the
opinion of my company. Unless I say so.


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Elvis Budimlic
Sent: Tuesday, September 11, 2007 4:23 PM
To: 'Midrange Systems Technical Discussion'
Subject: RE: CREATE INDEX and name only some columns

You can't create an index over a view.
You can create an index over select columns from the underlying
physical file (SQL table).

If you're referring to this index looking in DSPFFD as a
keyed LF that
lists all the fields from the underlying PF, there is no way around
this. Only fields that are keyed are the ones you list on
the CREATE
INDEX statement, but they all show. So if you were to
access this SQL
index with native I/O (RPG), that's what you'd get.

Elvis

RPG & DB2 Summit | Minneapolis | October 1-4 Mike Cain -
DB2 for i5/OS
Temporary Indexes - The Good, The Bad, The Ugly October 16
2007 System i Fall Technical Conference | Orlando | November
4-7 Celebrating 10-Years of SQL Performance Excellence on
IBM System
i, eServer iSeries and the server affectionately known as the AS/400

-----Original Message-----
From:
midrange-l-bounces+ebudimlic=centerfieldtechnology.com@xxxxxxxxxxxx
[mailto:midrange-l-bounces+ebudimlic=centerfieldtechnology.com
@midrange.com]
On Behalf Of Jeff Crosby
Sent: Tuesday, September 11, 2007 3:17 PM
To: 'Midrange Systems Technical Discussion'
Subject: CREATE INDEX and name only some columns

Can I create an SQL index and name the columns so that I'm only
including specific columns from the base table instead of
all columns?

Or do I need to create a view, and then an index over the view
(because a view can't have a 'key')?

I've been looking for examples creating an index with specific
columns, haven't found any, and therefore I think I can't do it.

Thanks.

--
Jeff Crosby
UniPro FoodService/Dilgard
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531

The opinions expressed are my own and not necessarily the
opinion of
my company. Unless I say so.


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