xsd – XML Schema元素顺序

在我的XSD中,我希望能够指定元素的顺序并不重要.这是我有的：

<xs:element name="ADT_A08_231_GLO_DEF">
  <xs:complexType>
    <xs:sequence>
      <xs:element minOccurs="1" maxOccurs="1" name="EVN_EventTypeSegment" type="xs:string" />
      <xs:element minOccurs="1" maxOccurs="1" name="PID_PatientIdentificationSegment" type="xs:string" />
      <xs:element minOccurs="0" maxOccurs="1" name="PD1_PatientAdditionalDemographicSegment" type="xs:string" />
    </xs:sequence>
  </xs:complexType>
</xs:element>

如何使EVN和PID元素在XML文件中随机(先是EVN,然后是PID或第一个PID元素,然后是EVN元素)？

<EVN_EventTypeSegment>Test</EVN_EventTypeSegment>
<PID_PatientIdentificationSegment>PIDTest</PID_PatientIdentificationSegment>

要么：

<PID_PatientIdentificationSegment>PIDTest</PID_PatientIdentificationSegment>
<EVN_EventTypeSegment>Test</EVN_EventTypeSegment>

使用xs：all而不是xs：sequence.