Re: Calling DB/400 gurus - where to put DB keys physical or logical?

["R. Bruce Hoffman, Jr." <rbruceh@xxxxxxxxxxxxx>]

Rob's answer is on the mark.

just as an aside, SQL creates PRIMARY KEYS as keys on the PF.
Understand that if the index is in a logical, the logical can be set to
rebuild maintenance. This can cause the keys to become "dissassociated" from
changes in the physical and thus allow duplicate keys.
Even if the maintenance is set to rebuild or delayed in the physical, that
maintenance is changed to immediate when the file is open. When the data
needs to change, the physical must be opened. So there really is no way to
subvert unique, primary keys when they are on the physical.

I vote for puting them on the physical.

Also, keep in mind that indexes are tuning points and not access points for
SQL. As we move more towards SQL environments and make more use of RI,
logical files become essentially irrelavent for data CRUD operations.

===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified Specialist - iSeries Administrator
 -- IBM Certified Specialist - RPG IV Developer

"If you pick up a starving dog and make him prosperous,
  he will not bite you. This is the principal difference
  between a dog and a man."

    - Mark Twain

----- Original Message -----
From: "Villa, Mark" <mvilla@briggsplumbing.com>
To: <midrange-l@midrange.com>
Sent: Wednesday, October 16, 2002 9:32 AM
Subject: Calling DB/400 gurus - where to put DB keys physical or logical?


> I have always designed physical files with keys (unique ones).
> Now my eyes have been opened to a world of PF's that have no key that
> are always accessed with keyed logicals. To my surprise, this seems to
> be method of choice for some very common large scale software providers.
>
> I am thinking this matters greatly for future proofing, performance, and
> possible integration with other databases.
>
> My question: Is one way better than the other and what are the reasons?
>
>
> Mark Villa in Charleston SC
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