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Re: SOAP services as database query interfaces / SOAP design patterns?

From: Mark Baker <distobj@acm.org>
Date: Tue, 19 Nov 2002 09:46:18 -0500
To: Dan Brickley <danbri@w3.org>
Cc: www-ws@w3.org
Message-ID: <20021119094618.R21537@www.markbaker.ca>

Dan,

I think it's important to note that most of those services you refer to
at XMethods would best be implemented using either vanilla HTTP GET, or
HTTP GET via the SOAP 1.2 WebMethod feature[1].  For really complex
queries, where URIifying the query terms is not practical, the use of
SOAP/POST may be beneficial, but there's even much better ways to do
that[2] than most Web services use.

So IMHO, I don't think there's much use in trying to optimize for them,
because query based Web services should be using the optimizations
already available in GET and URIs.

 [1] http://www.w3.org/TR/soap12-part2/#WebMethodFeature
 [2] http://lists.w3.org/Archives/Public/www-tag/2002Jan/0232

MB

On Mon, Nov 18, 2002 at 04:55:17PM -0500, Dan Brickley wrote:
> 
> 
> www-ws,
> 
> I was looking again at the registry of (public) SOAP Web Services at
> http://www.xmethods.com/ and was struck (again) by the fact that many,
> perhaps most, of these services appear to be based around database
> queries, ie. they return a single item or list of items corresponding to
> record(s) picked out by the argument(s) passed in the SOAP request.
> 
> Lottery results given a region and date. Car rental quotes given a query
> specification. Zipcode to lat/long mappings. Searches against Shakespeare
> etexts. Telephone codes from city names. Weather forecasts from zipcodes.
> Book data given ISBN. Whois lookups. Population size given countrycode.
> 
> etc etc. You get the idea. SELECT/FROM/WHERE-esque use cases.
> 
> So I'm interested in whether this recurring pattern of Web Service
> deployment can be captured for machine use, or less ambitiously, whether
> anyone has offered a more careful analysis than mine of the ways in which
> real live SOAP services are being deployed in the public Web as a way of
> exposing database lookup facilities. I'd like to be able to consult a
> database of SOAP services and pick out those which offer such lookup-based
> information services. I'd like to know which of those have an interaction
> pattern that typically returns a list of 'hits' versus which return a
> single 'hit'. I'd like to know how each service represents a search with
> zero hits versus a search that fails for some other reason (malformed
> query; database temporarily down etc.).
> 
> Basically it strikes me that there is a lot of hidden commonality across
> these lookup-based Web services, and that there would be significant
> benefit to having machine-friendly characterisations of aspects of that
> commonality. Many of them are probably thin wrappers for SQL queries and
> ODBC/JDBC/DBI anyway. My current understanding of WSDL and the Web Service
> Description effort is that it would support richer
> description/classification of these services, but doesn't come with innate
> support for representing these.
> 
> Um, I guess I'm rambling now. The purpose of this mail was to enquire
> whether folk on www-ws could point me to any work on classifying
> query/lookup based SOAP services, eg. using WSDL extensions, RDF/DAML-S etc.
> 
> Thanks for any pointers,
> 
> Dan
> 
> ps. this is related to my earlier enquiry about the use of W3C's XQuery
> for Web Service discovery, see thread beginning
> http://lists.w3.org/Archives/Public/www-ws/2002Jul/0001.html
> 
> 
> -- 
> mailto:danbri@w3.org
> http://www.w3.org/People/DanBri/

-- 
Mark Baker.  Ottawa, Ontario, CANADA.   http://www.markbaker.ca

   Will distribute objects for food
Received on Tuesday, 19 November 2002 09:42:55 GMT

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