Re: D2RQ and Revelytix semantics

Hi Juan,

On 26 Jul 2010, at 21:51, Juan Sequeda wrote:

The D2RQ bits look good AFAICT.

> - Both mapping languages have the semantics established as
> Database-Instance-and-Schema Mapping [1] (there is a definition of  
> Classes
> and Properties).

D2RQ is *mostly* database-instance-only. If one uses an auto-generated  
mapping, one can optionally enable the generation of class and  
property definitions for the auto-generated class/property URIs. When  
the mapping author customizes the mapping and replaces the auto- 
generated URIs with URIs from shared vocabularies/ontologies, then  
these definitions are no longer needed.

> There is no way to formally prove this because both
> languages don't have existing defined semantics (right?)

The semantics of the D2RQ language is defined by the implementation,  
and documented in the manual ;-)

If you talk about *formally* defined semantics, you're right it  
doesn't have it.

> - Revelytix language has different ways of saying the same thing for  
> sake of
> query optimization ( right?). (I personally believe this is  
> something we
> should avoid. Language and implementation details should be  
> separate... just
> look at SQL)

In D2RQ there are a number of instances where one can say the same  
thing in different ways. This is mostly for author convenience --  
syntactic sugar.


> Looking forward to Alex's presentation tomorrow!
> [1]
> Juan Sequeda
> +1-575-SEQ-UEDA

Received on Monday, 26 July 2010 23:26:57 UTC