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Re: proposed additions for discovery, sorting, and typed values

From: Lisa Rein <lisarein@finetuning.com>
Date: Mon, 16 Mar 1998 12:12:26 -0800
Message-ID: <350D87AA.F9BB011C@finetuning.com>
To: "Saveen Reddy (Exchange)" <saveenr@Exchange.Microsoft.com>
CC: "DASL Working Group (E-mail)" <www-webdav-dasl@w3.org>
Hello all, 

We in the RDF Schema working group are also working with typing the
nodes of query resources along similar lines...

Our spec won't be public for a week or two (i don't think)...but I look
forward to integrating the functionality between all of these, and I
have been watching all of the great work going into DASL very closely.

XML-Data does have some lovely data typing mechanisims that I thing
would work quite nicely with DASL and WEBDAV, for searching and in
general overall.  

Ideally, these different specifications could be fully interoperable
with each other, providing a standardized universal searching and
querying mechanism for the whole web -- and all over HTTP.

keep up the good work, and consider me a resource if you have any
questions about the RDF schema spec when it arrives.


Lisa Rein
W3C RDF Schema Working Group

Saveen Reddy (Exchange) wrote:
> A few comments on your proposal, Jim ...
> Schema Discovery:
> The text describes a property for discovering which operators are supported.
> There's a particular case in which I'm interested here. Suppose a server
> offers searching on every resource -- making it easy for the client to
> perform searches, by essentially making every URI available as a search
> arbiter. In this case clients don't have to go find an arbiter -- they can
> whatever URI is at hand. Would the queryschema property have to be defined
> on each on of those resources? That seems like it be potentially a lot of
> data stored on each resource just to support the search method. A PROPFIND
> response that returned all properties might be very large when doen over a
> container (even if depth=1).
> My feeling if such a property would work best only if there where a small
> number of arbiters. One way to get around this and yet have discoverability
> for all resources is to use the DASL: part of the OPTIONS response; it could
> point the client to a resource that has the relevant queryschema property.
> This would allow the information to exist for any resource without the
> burden of actually defining the property on each searchable resource.
> Typing:
> We may want to leverage typing work that is already being done in XML. For
> example, XML-Data defines a number of types and a mechanism for doing typing
> in XML:
>         http://www.w3.org/TR/1998/NOTE-XML-data/
> Not all of this document deals with typing but there is a nice section on
> it. These types are very oriented to the kinds of searches we are talking
> about -- they basically match simple data types we are all familiar with.
> Thanks,
> -Saveen
> -----Original Message-----
> From: Jim Davis [mailto:jdavis@parc.xerox.com]
> Sent: Wednesday, March 11, 1998 10:02 PM
> To: www-webdav-dasl@w3.org
> Subject: proposed additions for discovery, sorting, and typed values
> DASL needs methods for sorting results and for schema discovery.  It also
> needs three valued logic and explicit typing.
> I have proposals for how to do all these.
> sorting is obvious, we add a sortby tag to the simplesearch.  The only
> tricky issues are 1) ensuring that one can also sort by 'relevance' as most
> full text search engines do, and 2) allowing one to sort up or down, and 3)
> finding a way to talk about differences in sorting order among various char
> sets.  My current proposal only addresses the first issue
> schema discovery means the ability to determine, for a given server, not
> only what query syntax it supports, but what properties are searchable,
> sortable, etc.   I suggest the way to do this is to say that for each
> searchable resource (an arbiter, as the current draft calls it), for each
> query syntax it supports, it define a property whose value is the (query
> syntax specific) schema.  For the simple search, this would list the
> searchable properties, available operators, etc.
> I have a detailed proposal for a set of tags to do this for simple search.
> We need data types so we can tell the difference between the string "7" and
> the number 7.  (Perhaps Alan B will send some email explaining more on this
> point.)
> We need three valued logic so we can search for e.g. resources where some
> properties might be undefined, and so we can handle things like divide by
> zero with clarity.  This means we also need constants for the true, false,
> and unknown values.
> Rather than send my specific proposal as a huge email file I have placed it
> on the Web, in both Word and plain text.  The plain text was generated from
> the Word and is not as nicely formatted but hopefuly conveys the ideas.
> Perhaps Saveen will be kind enough to pick up my Word file (that is, if he
> agrees with my proposals) and merge them into the official draft proposal.
> I should admit that the current proposal shows the syntax but does not
> explain or justify it very well.  If you've worked with lots of search
> systems than it may make sense, but otherwise I'll have to add more
> language to it.
> I just wanted to get it out now so there could be some discussion on the
> basic framework.  If there is agreement then we can pursue the details of
> syntax further.
> Please see
> http://www.parc.xerox.com/istl/members/jdavis/dasl-plus.doc
> http://www.parc.xerox.com/istl/members/jdavis/dasl-plus.txt
> Best regards
> Jim
> ------------------------------------
> http://www.parc.xerox.com/jdavis/
> 650-812-4301
Received on Monday, 16 March 1998 14:53:12 UTC

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