Re: Failed Chain question.

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 22/01/2009, at 1:31 AM, Brown, Stephen GRNRC wrote:

> Field Prdid is used in more than 1 file and shares the name  
> throughout.
>
> Say Prdid = 'A' from a previous file or move etc.
>
> Chain to another file that contains the field Prdid fails,  can the
> value of any of the records on this file overwrite the value of Prdid
> even though the chain actually failed.


How can an unsuccessful read (of any form) overlay existing data if  
the read itself failed? You didn't read a record so you have no  
values to overlay with.

Perhaps you think fields in a record format are replaced with default  
values (e.g., blanks and zeroes) on an unsuccessful read? No, that's  
not the case as is clearly explained in the RPG Reference manual:

If an input operation (CHAIN, EXFMT, READ, READC, READE, READP,
READPE) does not retrieve a record because no record was found,  
because an
error occurred in the operation, or because the last record was  
already retrieved
(end of file), then no data is extracted and all fields in the  
program remain
unchanged.

Regards,
Simon Coulter.
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