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RE: Moving DASL to Experimental

From: Julian Reschke <julian.reschke@gmx.de>
Date: Thu, 14 Jun 2001 12:33:30 +0200
To: "Babich, Alan" <ABabich@filenet.com>, <w3c-dist-auth@w3.org>
Message-ID: <JIEGINCHMLABHJBIGKBCIEDPCHAA.julian.reschke@gmx.de>
> From: w3c-dist-auth-request@w3.org
> [mailto:w3c-dist-auth-request@w3.org]On Behalf Of Babich, Alan
> Sent: Wednesday, June 13, 2001 9:39 PM
> To: 'Julian Reschke'; w3c-dist-auth@w3.org
> Subject: RE: Moving DASL to Experimental
>
> (stuff deleted)
>
>                                       ---
>
> I don't think putting data type information into the query on
> PROPERTIES is
> all that useful. After all, the server knows or should know about the data
> types of the properties it has stored.  I think that putting data type
> information on the LITERALS in the query would be much more useful. (For
> example, is "<literal>123</literal>" the integer 123 or the string "123",
> i.e., what did the client intend?) If data types are put on the literals,
> then even if the client doesn't know the data type of the property on the
> server, at least the server will know how to coerce the literal to the
> correct data type in cases where that is possible. (Some RDBMS's do, in
> fact, perform such coercions, e.g. Oracle.) The client can force the user
> choose what data type to enter for literals if it wants to, so the client
> can know what the user intends for the data type, even without
> query schema
> discovery.
>
> My suggestion of putting data types on the literals via attributes in the
> literal XML element was rejected, at least partly because people
> expected an
> XML committee to invent data types in XML itself. We, DASL, didn't want to
> do anything at variance with what that committee would come up with.
> Furthermore, we didn't think it was feasible to track what they were doing
> or to tie our schedule to theirs. A significant amount of time has elapsed
> since then, and I haven't tracked the XML data types effort. So, I don't
> know what the status of data types in XML is. If XML now has data
> types for
> literals, I would use them. If it doesn't, then, you have the same problem
> we did.

I think that putting datatype information into literals makes sense, and
with XML Schema (Part 2 I think) . I recently proposed a method for
specifiying data types upon PROPPATCH [1], a similar method could be
introduced for basicsearch as well, for instance:

<literal xsi:type="xs:dateTime">2001-06-14T13:31:00Z</literal>

As for querying structured properties, I think DASL should rely on the
technologies that have been defined for this (XPath). One could even
conceive writing the full query as XSLT :-).





[1] <http://lists.w3.org/Archives/Public/w3c-dist-auth/2001AprJun/0247.html>
Received on Thursday, 14 June 2001 06:33:57 GMT

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