Re: FW: how is XUpdate going?

[Tom Bradford]

On Wednesday, October 9, 2002, at 02:06  AM, Lars Martin wrote:
Luca, I forward your question to the xupdate mailing list. Please
subscribe to the list to join this discussion. Thanks, Lars.
On Tue,  8 Oct 2002 17:32:58 +0200 (CEST)

I only would like to know if there will be (or there is) a final 
version =
of XUpdate, because the latest XML:DB Working Draft review is from =
November 2000.

Thanks a lot.

Luc=EDa Mat=E9 G=F3mez
Universidad Carlos III de Madrid
Departamento de Ingenier=EDa Telem=E1tica.
I really believe that for XUpdate to have any overall value, it must 
support some form of dynamic evaluation for the content of modification 
constructs, and not just literal/static content.  Some associates and I 
have been developing the groundwork for a new XML query language...  A 
working man's query language, if you will.  It's called ViXEn (Verbose 
XML Expressions), is a pipeline language, and is for casual XML users 
rather than developers or highly technical people.  It supports both 
querying and modification syntaxes.  What follows are some notes that 
have been written up based on our discussions.

ViXEn - Verbose XML Expressions

ViXEn is a simple XML expression language geared toward XML users 
rather than developers.  It is not meant to provide an all-purpose 
general expression language for XML processing.  It is meant to provide 
functionality that addresses the most common use cases of simple XML 
processing from the perspective of a user.

It provides 20% the functionality of XQuery but addresses 80% of the 
requirements of real world XML users.  It is based partially on the 
XUpdate and SiXDML specifications with generous inspiration from SQL 
and the AppleScript language.

You'll notice that it abandons XPath as a node selection and filtering 
mechanism.  XPath is too cryptic and ambiguous for most (non-technical) 
XML users.  Other constructs that are happily missing include loops and 
parent axis traversal.

Example #1:
        from document "/work/dbXML/blah.xml"
        return all elements blah
Example #1.b:
        from document "/work/dbXML/blah.xml"
        get all elements blah
        then return all elements foo
Example #2:
        from document "/work/dbXML/blah.xml"
        get first element blah
                where value = "some value"
                and attribute id = 100
Example #2.b:
        from document "/work/dbXML/blah.xml"
        get first element blah
                with attribute id = 100
        then return all elements foo
Example #3:
        from document "/work/dbXML/blah.xml"
        get first 10 elements blah
                with attribute id = 100
                and attribute type = "test"
        then insert into
        (from document "/work/dbXML/other.xml"
        get last element foo
                with attribute id = 100)
Example #4:
        from document "/work/dbXML/blah.xml"
        get first element blah
        then get value
        then insert that into
        (new element wizbang)
        then append after
        (get document "/work/dbXML/other.xml"
        then get last element foo
                with attribute type = "test")
        then store document "/work/dbXML/newblah.xml"
Example #5:
        from documents "/work/dbXML/*.xml"
        get first element foo
        then delete last element blah
                with attribute id = 200
Example #6:
        from documents "/work/dbXML/*.xml"
        delete all documents
                with first element foo
                with attribute id = 100
Example #7:
        from document "/work/dbXML/blah.xml"
        get first element foo
                with attribute id = 100
        then set value to "new value"
        then set attribute id to 200
JFlex/JavaCC grammars forthcoming.

--
Tom Bradford - http://www.tbradford.org/
CTO - The dbXML Group - http://www.dbxml.com/
Apache Xindice - http://xml.apache.org/xindice
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