Ghislain,
As always, I am impressed with the clarity and brevity with which you
express complex concepts.
Thanks!!
Jim
On 4/18/2016 2:58 AM, Ghislain Fourny wrote:
> Hi,
>
> With a database background, my perspective is that:
>
> 1. A data model is needed as soon as you want to validate (don't
> forget the PSVI :-) ), query, process data.
>
> 2. A database needs a data model (this is what Edgar Codd called data
> independence, a very important concept) that the query language can
> manipulate.
>
> 3. Syntax is a representation of the data model that can be used for
> interoperability and exchanging (importing, exporting) data between
> different vendors. I tend to see the data model as the upper layer and
> the syntax as the lower layer, maybe because I think of it in terms of
> abstraction layers.
>
> 4. Whether the syntax or the data model is designed first is more
> best-practice-related, and, as was said in the other thread, the order
> in which it was done for XML has historical reasons. In practice, an
> instance of the data model can be serialized to syntax and syntax can
> be parsed to an instance of the data model.
>
> 5. There is this same idea of syntax and data model for other data
> formats as well:
>
> - XML and JSON (and protocol buffers, BSON, etc to the extent that
> bits can be seen as a low level of syntax, too) are the syntaxes that
> correspond to document stores/hierarchical data.
> - CSV is the syntax that corresponds to relational databases and the
> relational model, queried with SQL.
> - XBRL is the syntax that corresponds to data cubes (OLAP, queried
> with MDX...) (I'm doing a bit of a stretch here, but that's how I see it).
> - RDF (or, to be more precise, RDF/XML, Turtle, etc) is the syntax
> that corresponds to graph databases and triple stores, queried with
> SPARQL.
>
> My 2 cents :-)
>
> Kind regards,
> Ghislain
--
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Jim Melton --- Editor of ISO/IEC 9075-* (SQL) Phone: +1.801.942.0144
Chair, ISO/IEC JTC1/SC32 and W3C XML Query WG Fax : +1.801.942.3345
Oracle Corporation Oracle Email: jim dot melton at oracle dot com
1930 Viscounti Drive Alternate email: jim dot melton at acm dot org
Sandy, UT 84093-1063 USA Personal email: SheltieJim at xmission dot com
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= Facts are facts. But any opinions expressed are the opinions =
= only of myself and may or may not reflect the opinions of anybody =
= else with whom I may or may not have discussed the issues at hand. =
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