2219 2005-09-14 19:20:05 +0000 R-227: identity constraints and xsi:nil 2007-04-27 15:36:11 +0000 1 1 1 Unclassified XML Schema Structures: XSD Part 1 unspecified All All CLOSED FIXED medium, hard, idc cluster resolved P4 normal --- 1 sandygao cmsmcq www-xml-schema-comments oldest_to_newest 6242 0 sandygao 2005-09-14 19:20:05 +0000 If an element selected by the field of an identity constraint has xsi:nil='true', is the value treated as missing? For example, is the following instance valid, given the schema. schema ------ <xml version="1.0"?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:element name="root"> <xsd:complexType> <xsd:sequence> <xsd:element ref="uid" maxOccurs="unbounded"/> </xsd:sequence> </xsd:complexType> <xsd:unique id="foo123" name="uuid"> <xsd:selector xpath=".//uid"/> <xsd:field xpath="."/> </xsd:unique> </xsd:element> <xsd:element name="uid" nillable="true" type="xsd:anySimpleType"/> </xsd:schema> instance -------- <xml version="1.0"?> <root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xsi:noNamespaceSchemaLocation="idF018.xsd"> <uid xsi:nil="true" xsi:type="xsd:string"/> <uid xsi:nil="true"/> </root> I think this should be valid since the xsi:nil attribute on the uid elements would be equivalent to the elements missing for the purposes of identity constraints. Either way 3.11.4 of Schema part 1 could use some clarification around xsi:nil. See: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2003JulSep/0024.html 14564 1 sandygao 2007-03-28 18:44:06 +0000 The WG discussed this at a face to face meeting on 28 March and decided to close it as FIXED. The necessary changes were adopted in a previous WG meeting. Briefly, when xsi:nil=true, it's treated as if the value is missing. So the attached example will be accepted by schema 1.1. Note that if <key> is used in place of <unique>, the xml document becomes invalid, because <key> requires that all fields are present and have values. 14731 2 sandygao 2007-04-16 13:28:30 +0000 Closing it on behave of the originator, who indicated that "The resolution seems fine and so the bug can be closed." 14905 3 sandygao 2007-04-27 15:36:11 +0000 Reply from the originator: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2007AprJun/0044.html