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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: [Fwd: Potential Gap (WAS Re: [owl-s] communication between
 Unless one is say, creating ad hoc SQL queries and sending them to a non-collocated database, why would deep schema information be necessary? I don't think many private holders of data will be too eager to expose all of the local schema information but they would be willing to negotiate services that equal reports. It is completely possible to expose the schema or to expose an interface schema that middleware then transforms into the local schema. As you say, Thomas, mappings. BTW, why would I need OWL to implement what is essentially a business object? I don't see the problem. What am I missing? Joe, you may be asking for ad hoc querying. If so, it is doable but not often done for external resources. Crystal Reports and ODBC make it possible. The trick, as you note, is that given a flat set of descriptions without the integrity information, the security objects, etc., it is hard to build a good query and easy to screw up a database if the ODBC connection is badly configured. For that reason, the service should provide the right codes and relationships for its set of queries available by the role of the authorized and authenticated querying agency. NCIC for example, has a set of standard queries. len From: Thomas B. Passin [mailto:tpassin@c...] Chiusano Joseph wrote: > I sent this e-mail over 24 hours ago to the W3C Semantic Web Services > Interest Group, and I did not receive any pushback (a gentle way of > saying I did not receive a reply ;). So I'm wondering if that is good or > bad.... > Here is a scenario: > ... > > At this point, we need the following to happen: > > (1) The Hotel Reservation Web Service must relay to the Travel Agent Web > Service the information that is missing, and > (2) The Travel Agent Web Service needs to obtain that missing > information from the Travel Agent relational database > > It is #2 above that I perceive as a current gap - i.e. unless the Travel > Agent relational database is sufficiently "semantically aware" (i.e. > perhaps it implements an OWL ontology whose classes and properties are > mapped to the database tables/fields respectively), there is no > efficient and accurate way that the required information can be obtained > from the Travel Agent relational database. > </Scenario> > This seems to be no different from any other data integration problem. In general, it is impossible to automatically map from one database schema to another, because most databases do not/cannot contain enough explicit schema and ontology information to do so. In many if not most cases, people will have to create the mapping, or at least to adjust an automatically-obtained mapping. If not a map, then a wrapper to make the database respond like, say, and rdf database. This is one reason I have never believed in the practicality of fully automated service composition (or fully automated web service discovery, for that matter, and for similar reasons). But if you say that the agents are only to operate within known domains, the mappings or wrappers could be prepared in advance, just as is done today. 
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