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THE XML REVOLUTION - TECHNOLOGIES FOR THE FUTURE WEB
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Design requirements
Quotes from the W3C Note "XML Schema Requirements" (Feb. 1999):
Design principles:
The XML schema language shall be
- more expressive than XML DTDs
- expressed in XML
- self-describing
- usable by a wide variety of applications that employ XML
- straightforwardly usable on the Internet
- optimized for interoperability
- simple enough to be implemented with modest design and runtime resources
- coordinated with relevant W3C specs
The XML schema language specification shall
- be prepared quickly
- be precise, concise, human-readable, and illustrated with examples
Structural requirements:
The XML schema language must define
- mechanisms for constraining document structure (namespaces,
elements, attributes) and content (datatypes, entities, notations)
- mechanisms to enable inheritance for element, attribute, and datatype
definitions
- mechanism for URI reference to standard semantic understanding of a construct
- mechanism for embedded documentation
- mechanism for application-specific constraints and descriptions
- mechanisms for addressing the evolution of schemata
- mechanisms to enable integration of structural schemas with primitive data
types
Unfortunately, their own XML Schema Recommendation does not fulfil all requirements
(self-describing, simple, concise, human-readable, ...)
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COPYRIGHT © 2000-2003
ANDERS MØLLER & MICHAEL I. SCHWARTZBACH
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