Re: relational database

The database is database because it has the ability to create a logical view
of the data that is different from the physical view which is the whole
reason for having one. That we are nuts and do not use the capability is our
problem( More like disaster).

As far as I know the S/34 or 36 had no such capability. You just brought in
the entire record.

On Tue, Feb 8, 2011 at 10:55 AM, Morgan, Paul <Paul.Morgan@xxxxxxxxxxx>wrote:

Rob,

Yes I do believe that data is relational. Just because you've stored two
different relational tuples on the same physical file doesn't mean it's not
relational. It's got a key which I can use to retrieve a detail record
directly by order number/line number. With the alternative CODASYL
hierarchal or network database I'd have to follow a pointer chain route
through the header to get to the detail. CODASYL databases have external
definitions too so external definitions do not define a relational database.

Paul Morgan

Principal Programmer Analyst
IT Supply Chain/Replenishment


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:
midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Tuesday, February 08, 2011 11:12 AM
To: Midrange Systems Technical Discussion
Subject: RE: relational database

I really do not think that the S/36, S/34 and their predecessors qualify
as relational database machines simply because they supported a chain by a
key instead of just RRN in RPG.

Do you really think the data below is relational?
A0000100012345Bubba 1313 Mockingbird Lane New York NY12345
A00001001XYZ123Steel Coil ...

Hey, I can chain to the first key by order number 00001 and line number
000 (indicates header record). And I can chain to the second by order
number 00001 and line number 001 (>0 indicates a detail line). Who needs
externally defined files? Apparently that's not even required to be
considered a relational system. Just an ability to chain by a key instead
of a RRN.

Rob Berendt
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Dept 1600
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From: "Morgan, Paul" <Paul.Morgan@xxxxxxxxxxx>
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date: 02/08/2011 10:38 AM
Subject: RE: relational database
Sent by: midrange-l-bounces@xxxxxxxxxxxx



David,

Do you only use relative record numbers to link records in different files
and never use an index? Only then would your database not be relational.

Paul

Principal Programmer Analyst
IT Supply Chain/Replenishment


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of David FOXWELL
Sent: Tuesday, February 08, 2011 8:48 AM
To: Midrange Systems Technical Discussion
Subject: RE: relational database

-----Message d'origine-----
De : midrange-l-bounces@xxxxxxxxxxxx

It's not that the database isn't relational -
it's that the majority of i users don't describe it
it using relational techniques.

That's what I mean. I didn't write the DDS and I don't know much of
relation techniques for DDS. But that makes MY data base non relational as
it hasn't been described as it should.
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