Re: OVRDBF FILE(myfile) TOFILE(myfile)

[Loyd Goodbar <loyd@xxxxxxxxxxxxxx>]

One reason may be to force the use of a particular logical file.

For instance, an RPG program is coded over PFILE1. Later, a logical file
LFILE1 is created with keys matching the RPG program's logic. Instead of
changing the RPG program to use LFILE1, perform an override instead.
Assuming PFILE1 and LFILE1 have the same format level identifier, no change
is required to the RPG program and you gain a performance increase due to
the access path.

Note, for SQL RPGLE programs, overriding a file to take advantage of indexes
is unnecessary. As long as the RPG program's SQL references the base table,
the SQL runtime will use any new indexes automatically.

Does the FILE() parameter have a library, such as FILE(OTHERLIB/LFILE1)?
Cross-library logical files are not a best practice, but sometimes happens
if management requires a strict separation between vendor code and in-house
code.

--Loyd

On Thu, Sep 2, 2010 at 3:50 AM, David FOXWELL <David.FOXWELL@xxxxxxxxx>wrote:

> All,
>
> I'm seeing a lot of old clp's doing this command before calling an rpg
> program. There are ovrdbf's for each of the files specified in the rpg.
> Can anyone explain the reason for doing this?
>
>
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