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Re: Spec review request: CSV on the Web

From: ashok malhotra <ashok.malhotra@oracle.com>
Date: Sun, 19 Apr 2015 10:01:54 -0400
Message-ID: <5533B552.9070308@oracle.com>
To: Dan Brickley <danbri@google.com>, Ivan Herman <ivan@w3.org>
CC: Jeni Tennison <jeni@jenitennison.com>, www-tag@w3.org, W3C CSV on the Web Working Group <public-csv-wg@w3.org>
Ivan, Dan:
Thank you for your replies.  I found the Wiki https://github.com/w3c/csvw/wiki/Deviations-from-the-charter
very helpful.  Could some of the material be incorporated in the main spec?  By metadata do you mean
column data types?  Couldn't these be specified by the user?

Dan, you said:
 > Another
 > angle is to note that
 > http://www.w3.org/TR/tabular-data-model/#datatypes +
 > http://www.w3.org/TR/tabular-data-model/#dfn-table-foreign-keys are
 > probably the most important reference for considering w.r.t. RDB/SQL
 > dumps, and that it might be useful to have an "at a glance" paragraph
 > (in our Wiki or blog if not in specs) for SQL-oriented readers that
 > could help encourage people with the appropriate expertise to create
 > tools that turn CSVs + W3C CSVW metadata back into e.g.
 > MySQL/PostGres/Oracle/etc SQL database creation scripts. Perhaps
 > Gregg's recent post at
 > http://greggkellogg.net/2015/04/implementing-csv-on-the-web/ even does this ...

Yes, a brief discussion in the spec would be good.

My higher-level point was this:  How can W3C's Data on the Web initiative be credible if
it ignores Relational data?  It has to be seen as being relevant to real enterprise users.


All the best, Ashok

On 4/19/2015 6:29 AM, Dan Brickley wrote:
> On 19 April 2015 at 09:06, Ivan Herman <ivan@w3.org> wrote:
>>
>>> On 19 Apr 2015, at 01:07 , ashok malhotra <ashok.malhotra@oracle.com> wrote:
>>>
>>> Shouldn't it be possible to create Relational tables from tabular data?
>>> That is, after all, a popular use of tabular data.
>>> There are probably existing tools and standards to do this but I would
>>> think it was worth at least a mention.
>>>
>>
>> Hi Ashok,
>>
>> I am not sure what you mean. At the moment, the group has produced (apart from the specification of the generic metadata for CSV files) a specification to convert a CSV file into simple JSON and into RDF. Do you mean to specify converting a CSV file into an RDB Table, essentially, to produce a Database Schema? I certainly see that this may be useful but (a) you seem to suggest that such tools and standards already exist for this, (b) the group certainly does not have the right expertise to do that (let alone not being chartered for it:-).
>>
>> What do you think is possible and worth doing under these circumstances? It is really not clear to me...
>
> Perhaps Ashok is alluding to the RDB2RDF efforts that he co-chaired,
> and that our charter refers to, i.e.
> http://www.w3.org/2013/05/lcsv-charter "The output of the mapping
> mechanism for RDF MUST be consistent with either the RDF Direct
> Mapping or R2RML so that if a table from a relational database is
> exported as CSV and then mapped it produces semantically identical
> data." The draft at
> https://github.com/w3c/csvw/wiki/Deviations-from-the-charter and re
> direct mappings https://github.com/w3c/csvw/issues/455 are pertinent,
> articulating how the CSVW csv2rdf work corresponds to a basic RDB2RDF
> direct mapping and also explains why we didn't try to push the idea of
> using R2RML further, although we left in appropriate extensibility
> hooks.
>
> There is btw a rough experiment at
> https://github.com/w3c/csvw/blob/gh-pages/examples/tests/scenarios/chinook/attempts/attempt-1/chinook.rml.ttl
> (and nearby) that shows one way of applying a nonstandardized variant
> of R2RML ("RML") to this problem, mapping in that case several linked
> relational tables (serialized to CSV) into RDF. The Wiki link above
> explains why we didn't feel this line of enquiry was ready for the
> REC-track, although the approach we have taken puts in place several
> important pieces that would be necessary for R2RML-based mapping
> approaches to be fruitfully explored.
>
> Although conceptually a bundle of CSVs can seem very much like a
> relational database, the workflows, skills, incentives and tooling
> surrounding their publication can vary significantly from the RDB
> world. I believe we've found a reasonable and attractive tradeoff
> between simplicity and expressivity: the CSVW design maps similarly
> into both colloquial JSON and into reasonably expressive RDF, while
> providing hooks for other mapping approaches (both textual e.g.
> Mustache-style) and semweb (more complex RDF triple patterns via
> R2RML/RML) to be attached when the expertise and interest is there.
>
> But perhaps I am over-interpreting Ashok's "Shouldn't it be possible
> to create Relational tables from tabular data?" question. Another
> angle is to note that
> http://www.w3.org/TR/tabular-data-model/#datatypes +
> http://www.w3.org/TR/tabular-data-model/#dfn-table-foreign-keys are
> probably the most important reference for considering w.r.t. RDB/SQL
> dumps, and that it might be useful to have an "at a glance" paragraph
> (in our Wiki or blog if not in specs) for SQL-oriented readers that
> could help encourage people with the appropriate expertise to create
> tools that turn CSVs + W3C CSVW metadata back into e.g.
> MySQL/PostGres/Oracle/etc SQL database creation scripts. Perhaps
> Gregg's recent post at
> http://greggkellogg.net/2015/04/implementing-csv-on-the-web/ even does
> this, i.e. a Postgres expert reading that blog post and building on
> top of https://github.com/ruby-rdf/rdf-tabular might find it trivial
> to write import/export tools.
>
> Dan
>
Received on Sunday, 19 April 2015 14:02:40 UTC

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