RE: Concatenation of files

A logical over multiple physicals uses key fields from each record to
position that record in the logical view.  The fields need not be the same
name or position in each file, simply compatible in size and type.

Note that this is not a JOIN logical, just a simple multi-physical logical.
We used this all the time in BPCS, primarily for MRP: you could include
orders, forecasts, shop floor allocations, planned orders, whatever, as long
as they had similar fields to use as key fields (in our case, item and
date).  In the DDS, you can set up different selection criteria for each
physical, and identify the fields you would be using to sort on.  When you
read the logical, it would interleave the records from all the physicals
according to the key sequence.

It was quite impressive, actually, even if it was a bit of a pain to explain
to newbies <grin>.

Joe

From: Darrell A Martin

This doesn't sound right. We have several multi-format logicals built on
physical files with radically different formats. Certain utility setups,
such as DBU in multi-record mode, don't work with such files, but that is
not a problem for the most part.

The original message didn't mention indexes. However, record order is
probably implicit in the question.

I *believe* we are running programs that depend on the order of records in
multi-format logicals. This suggests that these logicals are indeed
indexed (in some way) on values from different files. I would be
interested in the rules if this is not true. It might help solve some
long-term nagging problems.