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Re: ODBC driver for RDF?

From: Arnold deVos <adv@langdale.com.au>
Date: Wed, 21 Nov 2001 17:01:00 +1100
Message-ID: <006801c17251$e7dd1df0$ea01a8c0@lakes.com.au>
To: <www-rdf-interest@w3.org>
> > > I was trying to explain RDF to my sister who makes her living building
> > > database backed websites with Cold Fusion,

funny coincidence, I was having a similar conversation with my sister who
also does cold-fusion websites.

>
>      SQL      RDF
>      ===      ===
>      table    Class
>      column   Property
>      row      object ("Resource")
>
> Unfortunately, this assumes all properties are daml:UniqueProperties.
> daml:UnambiguousProperties would be SQL UNIQUE KEY columns.
>
> Maybe non-UniqueProperties should be handled by having more rows which
> have otherwise-the-same column data.

You also have to deal with missing statements.  I suppose you would report a
database null for column C of row R when there is no statement of the form
(R, C, x).

Conversely, some ODBC and JDBC operations assume that all the columns for a
table are known in advance of delivering the rows.

In RDF terms that might translate as the set of properties whose domain is
the given class (if schema information is available and is considered
complete).  Otherwise, one could evaluate the set of properties actually
applied to any instance of the class.

- Arnold
Received on Wednesday, 21 November 2001 00:56:00 GMT

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