为什么将 用于单个 ？

Question

<xsd:complexType>
<xsd:sequence>
<xsd:element name="allowFieldTruncation" type="xsd:boolean"/>
</xsd:sequence>
</xsd:complexType>

在上面的示例中，我只有一个元素（称为allowFieldTruncation）在复杂类型下定义，并且对minOccurs或maxOccurs]没有要求。现在我的问题是为什么我应该包含一个序列标签–定义不能像下面吗？

<xsd:complexType>
<xsd:element name="allowFieldTruncation" type="xsd:boolean"/>
</xsd:complexType>

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Answer 1

因为XSD规范says so：

<complexType
  abstract = boolean : false
  block = (#all | List of (extension | restriction))
  final = (#all | List of (extension | restriction))
  id = ID
  mixed = boolean : false
  name = NCName
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?, 
            (simpleContent | complexContent 
            | ((group | all | choice | sequence)?, 
               ((attribute | attributeGroup)*, anyAttribute?))))
</complexType>