- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Tue, 27 Jul 2010 00:26:21 +0100
- To: Juan Sequeda <juanfederico@gmail.com>
- Cc: Alex Miller <alexdmiller@yahoo.com>, public-rdb2rdf-wg@w3.org
Hi Juan, On 26 Jul 2010, at 21:51, Juan Sequeda wrote: > https://docs.google.com/document/pub?id=1APTqD2lJLRjwV6gmPKqDRqC3aT8bozHF0udIXndMNWQ 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. Best, Richard > > Looking forward to Alex's presentation tomorrow! > > > [1] > http://www.w3.org/2001/sw/rdb2rdf/wiki/Database-Instance-Only_and_Database-Instances-and-Schema_Mapping > > Juan Sequeda > +1-575-SEQ-UEDA > www.juansequeda.com
Received on Monday, 26 July 2010 23:26:57 UTC