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For me, it's not an issue of "how do I represent this data?", but "how do I
define this data so that it can be represented several different ways?"
There's certainly a lot of effort being expended in the development of
mapping between relational and object models, and between object models and
XML document models right now. The problem is that all mapping technologies
seem to require a primacy of one model over the other. For example, I can
generate class defs from a document model (Castor, JAXB), or I can generate
document models from class definitions (JiBX).
Is there a universal mapping language that can be used across all data
representations (a.k.a. mediums)? At the risk of sounding like a thrall of
certain fascists, I really do think that any such universal mapping language
will, at it's heart, be formulated on relational algebra. That's not to say
that all models must conform to integrity constraints under all operations;
what it does say is that those potential integrity violations are understood
and handled correctly when data is moved from one representation to the next
through the defined mapping operations.
I believe we're a long way from getting a mapping language that's both
universal and easy to use. It may be a language with many dialects, each
suited from a particular set of representations and mapping direction. It
does seem, though, that the current technique of writing one-off Java, C++,
and XSLT algorithms to perform these representational transforms is horribly