Re: Deleting all records in a PF

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 05/04/2005, at 3:43 AM, Douglas W. Palme wrote:

> I know that I can use SQL to completely clear a physcial file, and in 
> the
> end I might end up doing just that, but for educational purposes, what 
> does
> everyone consider the easiest method of clearing all records using 
> strictly
> RPGLE?

CLRPFM via a CL program or QCMDEXC will be easiest and fastest because 
it simply truncates the data space. You need exclusive access to the 
file and it can't have any trigger programs defined.

Pure RPG would be:

C                               DOU                     NOT(%FOUND(filename))
C                               EVAL        rrn = rrn + 1
C               rrn             DELETE          filename
C                               ENDDO

but does rely on there being no deleted records in the file. A slower 
alternative would be:

C                               READ            filename
C                               DOW                     NOT(%EOF(filename))
C                               DELETE          filename
C                               READ            filename
C                               ENDDO

which would delete all records in the file.

You could also determine the number of records in the file from the 
file feedback data structure and use that to ensure you delete all the 
records by ignoring records not found until you had deleted as many 
records as the file contained at open. You may have to allow for other 
applications adding records to the file while you are deleting the ones 
you know about with this method.

Regards,
Simon Coulter.
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