Re: OOP/OOD Philosophy

> Regardless of the extra code to support queries in XML, we don't want this
> change to drag down the rest of our modules. The change should be isolated
> to the Persistence Layer.

The question is if really need switchability between different data
paradigms. In history there have been three -hierachical, network and
relational. All but relational is obsolete. There might come new
paradigms, but it seem to take at least 10-20 years between every
generation. As pointed out in my answer to Feathers it is impossible to
know how a future paradigm would affect the application structure, so
trying to prefare for an unknown future in this case, is just wast of
money.

Once we identified the need for a RDBMS in an application, we can be
resonable sure that a RDBMS could be used during the entire life-cycle
of the application. The good thing with modern relational databases is
the high level of standardization. If a new generation of databases
would come soon, we can be sure that there would SQL support and
JDBC/ODBC/ADO drivers to emulate relational databses in the next
generation databases.

I think you base your argument on the fact that yesterday databases had
a very low level of standardization. If you changed vendor, you had to
rewrite your application. But today it is easy to separate your
application from a database vendor by using standard interfaces.

Fredrik Bertilsson
http://butler.sourceforge.net

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