Re: Chain vs SetLL/ReadE

Terry

Thanks - that is the other form of the READx loop - I guess I don't care for it, as you have 2 comparisons for every time through instead of 1 - I think!! Might get optimized away in any case, but we don't know that.

Seems to be we pays our money and takes our choice!

Vern

-------------- Original message --------------
From: Terrence Enger <tenger@xxxxxxxxxxxxxxxx>

On Tue, 2008-09-02 at 08:34 -0500, Chandra Krieg wrote:

Hello all,

I have been told that the preferred method of random record retrieval is to

use the SetLL, then do a ReadE and check for the %EOF indicator.

Why is this preferred over using a Chain with %found or even checking for

%Equal on the SetLL before reading the file? I have been told that the Chain
doesn't do what I'm expecting it to but I've never had issues in the past.

I have read the archive posts and found opinions on the subject but no

concrete explenation as to why. As with some of the posts I don't understand
why you would want to readE the file if the SetLL didn't find an %equal match or
why if you plan to read the file a chain isn't appropriate.

I'm being told to use the following code instead of a Chain.

SetLL (KeyFields) FIleName;
ReadE (KeyFields FIleName;
DoW Not %EOF(FIleName);
do my stuff
ReadE (KeyFields) FileName;
EndDo;

Well, I can imagine that it might be deemed a bit simpler to avoid
having both a CHAIN and a READE for one file in one chunk of code. But
my own taste would be to have only one READE, even at the cost of two
more lines of code.

SetLL (KeyFields) FileName;
DoW 0=0;
ReadE (KeyFields) FileName;
if %eof( FileName );
leave;
endIf;
do my stuff
EndDo;

Hope I do not sound too much like a broken record.

Cheers,
Terry.

Any explanations would be helpful!

TIA!

Chandra Krieg
i5 Programmer/Analyst
RateWatch
(P) 1.800.348.1831 ext 311
(F) 1.920.568.1403
www.rate-watch.com

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