Identical field names (was RE: SQL explained)

["Tim Kredlo" <TKredlo@xxxxxxxxxxxxxxxx>]

I see some potential advantage of having field names be identical, but I
gave up attempting to do this when I realized the extra work required to
make this happen.

For example, our parts file has 2 fields in it containing a part#. The first
is the unique ID for the record itself, the other is the unique ID for a
different record in the same file.

Another example would be our sales order file, where the header record for
the order contains 2 customer#s, the 'sold-to' customer# and the 'ship-to'
customer#. Both fields refer to the unique, but not necessarily the same,
customer# in our customer master. Since these 2 fields cannot be named the
same, it is impossible for both of them to be the named the same as the
unique ID in the customer file. We could have created multiple record
formats, or used multiple files, but as it is, retrieving one record from
one sales order file gets me both customer#s.

It may be considered 'best practices', but it seems to me that this 'rule'
prevents one from referencing more than a single record in another file from
a single record, even if  for different reasons, as in the sales order
example. Am I missing something here?

Tim Kredlo
Exterior Wood, Inc



-----Original Message-----
From: midrange-l-bounces+tkredlo=exteriorwood.com@xxxxxxxxxxxx
[mailto:midrange-l-bounces+tkredlo=exteriorwood.com@xxxxxxxxxxxx] On Behalf
Of Raul A. Jager W.
Sent: Wednesday, March 30, 2005 4:50 AM
To: Midrange Systems Technical Discussion
Subject: Re: SQL explained


Use "prefix" in your RPG programs...

Steve Landess wrote:

>> Rob wrote:
>>  For example some of the code presented is V5R3.  Prior to V5R3  LEFT 
>> OUTER JOIN CUSTMAST USING (SLSPSN)) Would have had to be written as
>>  LEFT OUTER JOIN CUSTMAST ON SLSPSNF.SLSPSN = CUSTMAST.SLSPSN)
>> Now, many people might still have to use this method because (IMNSHO) 
>> of a
>> poor design standard of naming the fields differently.  Example
>>  LEFT OUTER JOIN CUSTMAST ON SLSPSNF.SLSLSP = CUSTMAST.CSSLSP)
>
>
> Rob - since when did it become a "best practice" to use the same field 
> name multiple files?
>
> I have alway been taught that it is NOT a best practice, particularly 
> since in RPG if the field names are the same, the buffer storage 
> occupied by the field is global, and by READing or CHAINing you could 
> accidently overlay the value of a field in one file with the value of 
> the same field in another file, causing unpredictable results.
>
> Care to explain your reasoning?
>
> Regards,
> Steve
>


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