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Re: R2RML draft - new introduction

From: Richard Cyganiak <richard@cyganiak.de>
Date: Fri, 15 Oct 2010 13:21:28 +0100
Cc: Souri Das <Souripriya.Das@oracle.com>, ashok.malhotra@oracle.com, RDB2RDF WG <public-rdb2rdf-wg@w3.org>
Message-Id: <8A258085-D4A5-4C45-8B3B-AC2375E1FBD8@cyganiak.de>
To: Juan Sequeda <juanfederico@gmail.com>
Juan,

On 14 Oct 2010, at 20:09, Juan Sequeda wrote:
>> The output graph has to contain information that's in the database  
>> tables.
>> So the tables themselves have to be part of the input.
>>
>
> A relational schema consists of tables.

You are right (and so is Ashok), and I was wrong.

In my head, a “schema” is something that describes the structure of  
some data, and is distinct from the “actual” data. That's how the term  
is used in “XML Schema” and “RDF Schema”.

But having started to read the actual definitions of terms in the SQL  
spec, I now realize that a “SQL-schema” is indeed not just a  
collection of *table definitions*, but a collection of *tables* (and  
other stuff), consisting of columns and rows. So a SQL-schema includes  
the actual data.

I will update the draft to reflect that.

Sorry for the noise caused by my confusion. A bit embarrassing.

Best,
Richard
Received on Friday, 15 October 2010 12:22:10 UTC

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