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RE: Picking the Tools -- Marrying processing models to data model s
- From: Jeff Lowery <email@example.com>
- To: 'Al Snell' <firstname.lastname@example.org>,Uche Ogbuji <email@example.com>
- Date: Tue, 22 May 2001 12:02:03 -0700
> > maintenance. A trememdous side-effect of XML adoption is that it's
> > encouraging developers to finally start putting these matters in the
> > right order.
> How is this different from the days of SQL databases?
Hierarchical to relational mapping is harder than hierarchical to
hierarchical mapping. There's no silver bullet, but the doors open to create
a data model maps well to a class's type and containment hierarchy. For
example, XML Schema describes both. Whether is maps well to Java or C++ is
an open question, although groups are working on it.
And SQL databases will be around a long time yet. On problem in mapping
class data to databases is finding the class data to store and navigating to
it. The other is making sure the class constraints that control input match
those that are defined in the database schema, or you'll get runtime
problems. The reverse process, DB->class members is much fun either.
At least with a schema that describes internal data structure operated on by
the class, the constraints and structure can more easily be ascertained and