Re: [xml-dev] Automated schema migration

["Renaud Waldura" <renaud+xml@waldura.com>]

Michael and others:

Thank you for your answers. I understand that it is not be possible to infer 
relationships between 2 schemas, but I was referring to a transformation 
between schemas.

Let me re-express my initial message, because I feel it might have been 
understood. (I also have a thick skull, so I apologize if I'm the one who's 
not understanding you.)

Say I have a schema for the old document set, and a transformation that 
creates the new schema from the old -- a transformation between schemas. 
This transformation creates the new schema from the old.

Could I somehow derive a transformation between documents from this 
transformation between schemas?

Thanks again,

--Renaud

PS: I didn't know about mapping tools, I'll look into them.




----- Original Message ----- 
From: "Michael Kay" <mike@saxonica.com>
To: "'Renaud Waldura'" <renaud+xml@waldura.com>; <xml-dev@lists.xml.org>
Sent: Wednesday, November 09, 2005 2:01 PM
Subject: RE: [xml-dev] Automated schema migration


>> My question is: assuming I've created a schema for my old set
>> of documents,
>> if I were to create a transformation T1 that, given the old schema,
>> generates the new schema, could I machine-generate from that
>> transformation
>> T1 another transformation T2 that could be applied to the documents
>> themselves?
>
> It's easy to demonstrate that this is impossible in general. Given a 
> schema
> for
>
> <p>Some <i>text</i> in italics</p>
>
> and another schema for
>
> <para>Some <italic>text</italic> in italics</para>
>
> It's clearly impossible to deduce the transformation by looking at the
> schemas alone.
>
> There are plenty of tools out there (generally called "mappers") that 
> allow
> you to design a transformation starting from two schemas, by showing the
> relationships between the elements in each. They only work where the two
> schemas are quite similar, but that's probably true in your case.
>
> Michael Kay
> http://www.saxonica.com/
>
>
>
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