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[Help Me Understand] Part 1 Structures, Section 5.11 Complex Type Definition Constraints - Type Derivation OK

From: Asir S Vedamuthu <asirv@webmethods.com>
Date: Thu, 4 May 2000 09:59:09 -0400
To: "Henry S. Thompson" <ht@cogsci.ed.ac.uk>, <www-xml-schema-comments@w3.org>
Message-ID: <NDBBIAKBICMNDPDGIKPPKEAPCEAA.asirv@webmethods.com>
I am having a hard time to understand - how to evaluate 'The item type
definition is validly derived from the {type definition}'. And, here is the
text from the spec, http://www.w3.org/TR/xmlschema-1/#coss-ct

Constraint on Schemas: Type Derivation OK (Complex)

A complex type definition (call it D, for derived) is validly derived from a
type definition (call this B, for base) given a subset of {extension,
restriction} if: 1.1  The {derivation method} of D is not in the subset, or
in the {final} of its {base type definition};
1.2  Either 1.2.1  They are the same type definition;
or 1.2.2  B is the {base type definition}
or 1.2.3  the {base type definition} is not the ur-type definition and is
validly derived from B given the subset as defined by this constraint (if
the {base type definition} is complex) or validly derived from B given the
subset unioned with {list} as defined in Type Derivation OK (Simple) (?5.12)
(if the {base type definition} is simple). </Snip>

Please help me understand (may be an example) & I greatly appreciate your

All the best,

Asir S Vedamuthu
webMethods, Inc.
(Phone) 703-460-2513 (Fax) 703-460-2513 (E-mail) asirv@webmethods.com
URL: http://www.webmethods.com
Received on Thursday, 4 May 2000 09:57:48 UTC

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