XML Schema校验报错：元素不允许出现id属性，求解决办法

Hey there! Let's get this validation error sorted out for you. The error you're seeing (cvc-complex-type.3.2.2: Attribute 'id' is not allowed to appear in element 'System') has two key issues we need to address:

1. The id attribute isn't declared in your XSD #

Your XML's <A:System> element includes an id attribute, but your current XSD doesn't specify that this attribute is allowed for the System element. To fix this, you need to add an <xs:attribute> definition inside the xs:complexType block of the System element.

Updated XSD with id attribute support: #

<xs:element name="System" maxOccurs="unbounded"> 
  <xs:complexType> 
    <xs:sequence> 
      <xs:element name="SystemCd" /> 
    </xs:sequence>
    <!-- Add this to declare the 'id' attribute -->
    <xs:attribute name="id" type="xs:string" use="required" />
  </xs:complexType> 
</xs:element>

• Use use="required" if the id attribute must always be present (like in your XML example). If it's optional, change this to use="optional" or omit the use attribute entirely (optional is the default behavior).

2. Mismatched opening/closing XML tags #

Looking at your XML snippet, there's a critical tag mismatch: you start with <A:System> but close with </A:SourceSystem>. This will cause a separate validation error even after fixing the attribute issue. Correct the closing tag to match the opening one:

Corrected XML: #

<A:System id="systemName"> 
  <A:SystemCd>001</A:SystemCd> 
</A:System>

Apply both these fixes, and your XML should validate against the updated XSD without any errors.

内容的提问来源于stack exchange，提问作者Robert Price