RE: Logical File or OPNQRYF or any other way ?-Legacy iSeriesFlatFiles

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

This is a crucial distinction.  The fact is that many iSeries
programmers have not used the features (referential integrity, cascaded
deletes, etc.) that an RDBMS supports.  We tend to program them
ourselves.  And thus you see a lot of iSeries databases with no
higher-level definitions.  We might even assume there are no benefits to
the relational rigmarole, because we've never used it and never needed
it.  That would be a bad assumption, because there may well be things in
a relational database that we can take advantage of.

On the other hand, somebody who has defined keys and constraints and
such for their entire programming career is likely to look at a
barebones iSeries database and conclude that the iSeries is not
relational.  They would also be wrong.

The truth of the matter is that, like so many things on the iSeries, you
can do it however you prefer.  You can create a fully blown,
relationally defined database using nothing but SQL statements.  Or, you
can create a complete ISAM database using nothing but DDS.  Or you can
do a sort of hybrid, using DDS and some CL commands like ADDPFCST.

My favorite refrain applies here: it's a business decision.

But to say that DB2/400 is not relational is to miss the forest for the
trees.  As Charles says, you can create a non-relational database in any
RDBMS; it's just that folks trained on an RDBMS tend to think
relationally first.

Joe


> From: Wilt, Charles
> 
> No the iSeries DBMS is an RDBMS.
> 
> It's just most databases implimented on it are not RDBs given the
current
> meaning of the term.
> 
> You need to differenciate between the OS/RDBMS and the application/DBs
> runing on it.
> 
> Note that you could define a DB without relationships in Oracle or SQL
> server as easy as you can in DB2 for iSeries.  You just don't see that
as
> often.