XSD：如果可選父項存在，則需要嵌套標記

Question

我有我的XML中可選的標記，如果可選標記存在，那麼我需要該元素的子標記是必需的，我如何使用XSD（或另一種解決方案，如果這在XSD中是不可能的）？我的XML的

部的一例的：

   <xs:element name="deviceLocation" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
        <xs:complexType> 
        <xs:sequence> 
         <xs:element type="xs:string" name="xPos"/> 
         <xs:element type="xs:string" name="yPos"/> 
         <xs:element type="xs:string" name="zPos"/> 
        </xs:sequence> 
        </xs:complexType> 
       </xs:element> 

正如你可以看到deviceLocation標籤是可選的 - 如果此標記存在，我再要孩子標籤需要xPos，yPos和zPos。

編輯：這樣的要求

<?xml version="1.0" encoding="UTF-8"?> 
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"> 
    <xs:element name="homeML"> 
    <xs:complexType> 
     <xs:sequence> 
     <xs:element name="inhabitantDetails" minOccurs="1" maxOccurs="unbounded"> 
      <xs:complexType> 
      <xs:sequence> 
       <xs:element name="inhabitantID" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="name" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="carePlan" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="comment" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
      </xs:sequence> 
      </xs:complexType> 
     </xs:element> 
     <xs:element name="location" minOccurs="1" maxOccurs="unbounded"> 
      <xs:complexType> 
      <xs:sequence> 
       <xs:element name="locationID" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="locationDescription" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="referenceObjects" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="locationDevice" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
       <xs:complexType> 
        <xs:sequence> 
        <xs:element name="lDeviceID" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
        <xs:element name="deviceDescription" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
        <xs:element name="deviceLocation" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
         <xs:complexType> 
         <xs:sequence> 
          <xs:element name="xPos" type="xs:string" minOccurs="0"/> 
          <xs:element name="yPos" type="xs:string" minOccurs="0"/> 
          <xs:element name="zPos" type="xs:string" minOccurs="0"/> 
         </xs:sequence> 
         </xs:complexType> 
        </xs:element> 
        <xs:element name="units" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
        <xs:element name="realTimeInformation" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
         <xs:complexType> 
         <xs:sequence> 
          <xs:element name="runID" type="xs:string" minOccurs="0"/> 
          <xs:element name="sampleRate" type="xs:string" minOccurs="0"/> 
          <xs:element name="startTimeStamp" type="xs:dateTime" minOccurs="0"/> 
          <xs:element name="endTimeStamp" type="xs:dateTime" minOccurs="0"/> 
          <xs:element name="data" type="xs:string" minOccurs="0"/> 
         </xs:sequence> 
         </xs:complexType> 
        </xs:element> 
        <xs:element name="event" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
         <xs:complexType> 
         <xs:sequence> 
          <xs:element name="lEventID" type="xs:string" minOccurs="0"/> 
          <xs:element name="timeStamp" type="xs:dateTime" minOccurs="0"/> 
          <xs:element name="data" type="xs:string" minOccurs="0"/> 
         </xs:sequence> 
         </xs:complexType> 
        </xs:element> 
        </xs:sequence> 
       </xs:complexType> 
       </xs:element> 
      </xs:sequence> 
      </xs:complexType> 
     </xs:element> 
     <xs:element name="mobileDevice" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
      <xs:complexType> 
      <xs:sequence> 
       <xs:element name="mDeviceID" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="deviceDescription" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="units" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="devicePlacement" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="quantisationResolution" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="realTimeInformation" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
       <xs:complexType> 
        <xs:sequence> 
        <xs:element name="runID" type="xs:string" minOccurs="0"/> 
        <xs:element name="sampleRate" type="xs:string" minOccurs="0"/> 
        <xs:element name="startTimeStamp" type="xs:dateTime" minOccurs="0"/> 
        <xs:element name="endTimeStamp" type="xs:dateTime" minOccurs="0"/> 
        <xs:element name="data" type="xs:string" minOccurs="0"/> 
        </xs:sequence> 
       </xs:complexType> 
       </xs:element> 
       <xs:element name="event" minOccurs="0" maxOccurs="unbounded" nillable="true"> 
       <xs:complexType> 
        <xs:sequence> 
        <xs:element name="mEventID" type="xs:string" minOccurs="0"/> 
        <xs:element name="timeStamp" type="xs:dateTime" minOccurs="0"/> 
        <xs:element name="data" type="xs:string" minOccurs="0"/> 
        <xs:element name="support" type="xs:string" minOccurs="0"/> 
        </xs:sequence> 
       </xs:complexType> 
       </xs:element> 
      </xs:sequence> 
      </xs:complexType> 
     </xs:element> 
     <xs:element name="annotationDetails" minOccurs="1" maxOccurs="unbounded"> 
      <xs:complexType> 
      <xs:sequence> 
       <xs:element name="annotationID" type="xs:string" minOccurs="1" maxOccurs="unbounded"/> 
       <xs:element name="experimentType" type="xs:string" minOccurs="1" maxOccurs="unbounded"/> 
       <xs:element name="lDevice" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="mDevice" type="xs:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/> 
       <xs:element name="startTimeStamp" type="xs:dateTime" minOccurs="1" maxOccurs="unbounded"/> 
       <xs:element name="endTimeStamp" type="xs:dateTime" minOccurs="1" maxOccurs="unbounded"/> 
      </xs:sequence> 
      </xs:complexType> 
     </xs:element> 
     </xs:sequence> 
    </xs:complexType> 
    </xs:element> 
</xs:schema> 

Answer 1

如果要聲明一個（孩子）全部架構元素：

<xs:element name="n" minOccurs="0" type="someType"/> 

則該元素是可選的，但如果真的發生了，那麼它必須符合類型someType。因此，如果someType定義了包含強制元素的內容模型，那麼n是可選的，但是當存在時，n的子元素是強制性的。

順便說一下，它的元素是可選的，而不是標籤。一個元素通常有兩個標籤，一個開始標籤和一個結束標籤。