RE: DB2

[Vern Hamberg <vhamberg@xxxxxxxxxxxxxxxxxxxxxxxxx>]

DB2/400, or DB2/UDB for iSeries, is not a port of DB2 from the other 
platforms. It is the same engine, basically, that's been around since 1980 
and before (S/38). Yes, there are new things.

One of the differences I am aware of is the index structure. AIX DB2 can 
(does?) store index entries and data entries together (called clustering?), 
iSeries DB2 does not.

The optimizer in AIX is different and creates many better access plan trees 
than does the old (pre-V5R2) optimizer of iSeries. AIX performance was used 
as the goal for the new query engine, and its performance was orders of 
magnitude better in some areas than that of the iSeries.

Techniques from other DB2 versions are finding their way into iSeries, but 
not a wholesale port.

Why aren't new features going into DDS? Because a direction was taken. SQL 
is the future, can't dedicate scarce resources to anything else.

JMHO and a little of "been there"

HTH

Vern

At 07:40 PM 3/13/2003 +0100, you wrote:
> Just my 2 Eurocents on this topic.
>
> the old DDS-based file structure cannot be called relational in the 
> context as it used here to a RDB.
>
> And it is my opinion that IBM did not renamed the old integrated RDBM 
> system within the OS to DB/2: IBM ported DB/2 to the AS/400. Because if 
> the old RDBM system and DB/2 are the same, why is not DDS enhanced with 
> the new data types?
>
> Calling the old RDBM of the AS/400 DB/2 is therefore a mistake, because 
> DB/2 relies more on SQL than the old RDBM system.
>
> With SQL you work with a database, which is a collection of tables. To get 
> the relationality between those tables you use referential integrity rules 
> with constraints and triggers.
>
> Regards,
> Carel Teijgeler.
>
>
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