- From: Jim Davis <jdavis@parc.xerox.com>
- Date: Wed, 11 Mar 1998 22:01:59 PST
- To: www-webdav-dasl@w3.org
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 Thursday, 12 March 1998 01:02:45 UTC