RE: ODBC (was RE: Green screen - it's time is over )

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> -----Original Message-----
> From: Brad Jensen
>
> > This ability to change the underlying physical layout
> (including, for
> > example, the fact that a file is physically moved to another
> machine, or
> > even another data format entirely) is the primary reason that a
> > message-based architecture is so preferable to ODBC.
>
> This must be peculiar to IBM's ODBC for the AS/400. It's totally
> unfamiliar to me.

If you use ODBC and change the name of a column, the ODBC doesn't work.
This is the same on any ODBC implementation.  You can avoid the issues to
some degree on a query you use a "SELECT *", but we've discussed the various
reasons why that is bad programming practice.   Regardless, to identify
JOINs, ORDERs and so on you need to know the column names.  The point is:
changing column names breaks ODBC calls.


> Well ,it seems to me that with programming you can decouple the
> data representation at any level you choose.

Not if your client relies on knowledge of the table and column names of your
database!  That's the point of the entire discussion.  If the client is
dependent upon field names, it is tied to your database, and more
importantly, your database is tied to your client.  By decoupling the client
and the database through an intermediate messaging interface, you thereby
remove the dependence of one upon the other, and allow changes to occur in
one region that do not affect the other.

This is the basic premise behind tiered programming.

Joe Pluta
www.plutabrothers.com