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On Friday 24 October 2003 10:39, Ralph Hilken wrote:
> Hello Tyler:
> On Friday 24 October 2003 9:44 AM EDT, Tyler Close wrote:
> > please answer the original question: "How exactly does the
> > thing described by a schema differ from a data model?"
> This question has been brought up before on this list. It is names vs.
> contents vs. context. One person's date is not the same as another's.
> Probably the best way to explain it would be to present my challenge: "I
> can take your schema and write an XML document that will not meet your
> needs, rather my needs". If I were a nice guy, I might tell you what the
> document really means, as the schema will never tell you. This has been
> done over and over again in business computing, Just To Get The Job Done.
> Need to send new data fragments over an agreed upon protocol, but have no
> time to redo the schema, or the person that would do that is on vacation?
> Then it is time to find new meaning for old fields. If it is important
> enough, the schema can be updated at a later date. And so it goes...
This can also happen in a data model. I can certainly write code
that uses a different interpretation of any member in a C struct.