Re: Reading a joined file in RPG

Rob wrote:

> However, he just might be doing a join.

Could be.  I was going off of this: 'We have 1 file (non DDS) that has 12
formats'.  Doesn't sound like a good candidate for a join to me.

> Consider this, in a single physical with multi formats
> you do not need to replicate data
> 01-customer master
> 02-customer transaction
>
> 01cust#1
> 02bought some stuff
> 02bought more stuff
> 01cust#2
> 02bought some stuff
> 02bought more stuff
>
> But to break this out into different physical's so that you can
> externalize it, not duplicate customer# into each of the 02
> records, and still read them in the proper sequence, can
> be done how?

Great points.  In years past, we did things like put a running sequence
number at the end of each record, so the program that first touched the data
would simply read the records in sequence in the original flat file
(presuming some sort of data transfer) and build the multiple PFs with the
proper sequence numbers so that they'd all collate properly.  A different
approach would probably be to do exactly as you describe, and put cust,
item, line on each detail record so you'd have a good key list.

If I were doing this, I'd re-vamp the file layouts only slightly, so I could
put either the sequence number, surrogate key or natural keys at the end of
each PF.  There may be a larger issue if there are tagalong sorts or CPYFs
involved with this application (tinkering with record lengths may prove
unpleasant.)
  --buck