database file is not a mult occur ds. RE: programming languagegenealogy

["Steve Richter" <srichter@xxxxxxxxxxxxx>]

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Hans Boldt
Sent: Wednesday, May 28, 2003 8:48 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: Re: programming language genealogy


>Steve Richter wrote:
>> ...
>> A way to improve RPG is by integrating it even more to the OS.  Support
the
>> multiple occurance data struct as an object type in os/400.  Then access
the
>> mods in RPG just as it is used now.  Where the OS insures the integrity
of
>> the structure and serializes access.

>Multiple occurrence data structure as an object type in OS/400? You
>already have it - it's called a table in a relational database.

an academic point ...

What I am calling a "table" ( array/vector/mods ) object and a database file
object behave differently.  The most important is that the table is RRN
based, while a dbf is key based.  As rows are inserted into a table, the rrn
identity of each row is changed to reflect the rows new sequential position
in the table.  In a DBF the RRN stays the same.

The C++ STL recognizes the difference.  Where a "vector" is more array like
and static, while the "list" is dynamic, providing better performance for
inserts and deletes.

-Steve