Re: relational database

[Alan Campin <alan0307d@xxxxxxxxx>]

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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>
>
>
>
> 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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