Re: [xml-dev] Before creating a syntax, create an underlying datamodel

[Jim Melton <jim.melton@oracle.com>]

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
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