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XPath expressions in Identity Constraints..

From: Ravindra Jain <ravindra@ltp.soft.net>
Date: Tue, 29 May 2001 04:21:03 -0400 (EDT)
Message-ID: <001b01c0e818$e7401690$e701a8c0@LisleTechIN.ltp.soft.net>
To: <xmlschema-dev@w3.org>
Hi All,

I have some confusions over the "restricted XPath expressions" that can be
used in the "selector" and "field" xpath entries for Identity Constraints.

According to XML Schema Part 1 : Structures,

Selector Value must conform to the following extended BNF:
      [1]    Selector    ::=    Path ( '|' Path )*
      [2]    Path    ::=    ('.//')? Step ( '/' Step )*
      [3]    Step    ::=    '.' | NameTest
      [4]    NameTest    ::=    QName | '*' | NCName ':' '*'

Here  in above statement block, in the 4th statement,
I'm confused on the last phrase ( NCName ' : ' ' * ' )
what does it means ?

in the XPath specification, under section 2.3 (Node Tests),
some explanation is given for similar phrase ( NCName ' : ' ' * ' ).
But in the context of XML Schema, and identity constraints, how to interpret
this phrase.

According to my understanding, it means that select all the top level childs
of the namespace referred by the prefix (NCName).
Am I right ?
is there any other meaning for this ?

Thanks for your help.

With Best Regards,
Ravindra Jain
Received on Monday, 11 June 2001 05:35:45 GMT

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