RE: Re[4]: LVLCHK *NO

[Alan Campin <Alan.Campin@xxxxxxxxxxxxx>]

I think that is where the Data Mediator that appeared a few months ago in
Midrange Magazine comes into play. You call one program and it knows how to
map the data from any I/O service program back to you. You would still have
to write one service program per table to do the I/O but you would only have
one service program to include in your program.

Brilliant piece of work that guy did with that Data Mediator.  

-----Original Message-----
From: watern@CBS.FISERV.COM [mailto:watern@CBS.FISERV.COM]
Sent: Monday, October 04, 1999 1:41 AM
To: RPG400-L@midrange.com
Subject: RE: Re[4]: LVLCHK *NO


Alan wrote >

..<snip>.. The service program would just have a set of functions like,
OpenFile, Position File, ReadRecord, ReadNextRecord, etc....<snip>...

I like this idea of service programs for accessing files. I have seen it
done once before, with one service program per file. You told the program
what view you wanted, what operation (setll, reade etc) and a structure to
return the data in.  It was restricted to the six main master files.  It did
make the programming more cumbersome, but I can see the benefits of it.

I believe Lansa actually does something like this for database access, but
have no direct experience of the product myself.


..<snip>.. One of the first things I always hear when I discuss this method
is that you are creating a whole bunch of new indexes which is not correct.
As long as the AS/400 has an existing index, no matter how many times you
create another logical view of the data base, the AS/400 will maintain one
index only unless you specially override it and tell it to create a separate
index. ..<snip>..

I have come across this before. I am sure I heard that when recompiling
logical files, careful consideration of the order in which they are compiled
can make good use of this feature.  If File1 has key {order number, order
type} and File 2 has key {order number, order type, order date} then by
compiling File 2 first, File 1 will have an existing acess path it can use.
I hope I didnt misunderstand this.  I believe there is also a way of
determining how access paths are shared from one of the system commands...
does anyone know what this is ?

Nigel.


$ConflictAction: 1

+---
| This is the RPG/400 Mailing List!
| To submit a new message, send your mail to RPG400-L@midrange.com.
| To subscribe to this list send email to RPG400-L-SUB@midrange.com.
| To unsubscribe from this list send email to RPG400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator:
david@midrange.com
+---
+---
| This is the RPG/400 Mailing List!
| To submit a new message, send your mail to RPG400-L@midrange.com.
| To subscribe to this list send email to RPG400-L-SUB@midrange.com.
| To unsubscribe from this list send email to RPG400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---