使用 XSD 更清晰地扩展元素

发布于 2024-09-18 05:14:01 字数 3125 浏览 3 评论 0原文

我定义的 xml 模式包含一个名为“field”的元素和一个名为“composite-field”的扩展。它的定义如下：

<xs:complexType name="field">
        <xs:sequence>
            <xs:element name="value" type="xs:string" />
        </xs:sequence>      
</xs:complexType>
<xs:complexType name="composite-Field">
        <xs:complexContent>
          <xs:extension base="field">
            <xs:sequence>
                    <xs:element name="length" type="xs:integer" />
                  </xs:sequence>
                </xs:extension>
        </xs:complexContent>
</xs:complexType>

为了在我的 XML 中使用它，必须是：

<field xsi:type="composite-Field">
  <value>enjoy</value>
  <length>30</length>
</field>

我不希望我的 XML 用户使用架构语法，例如 xsi:type=..." " < br> 因此我的问题是：有什么方法可以使XML的语法为：

<composite-Field>
      <value>enjoy</value>
      <length>30</length>
</composite-Field>

这样元素的名称将暗示其继承性并且不会强制用户添加类型属性？

我尝试了这个：

<xs:element name="MyCompositeField" type="composite-field"/>

然后：

<MyCompositeField>
          <value>enjoy</value>
          <length>30</length>
</MyCompositeField>

但它也没有通过 XSD 架构验证

12/09/2010： 作为对建议答案的回应，我稍微改进了我的问题。
架构如下所示：

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 

    <xs:element name="general">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="field" type="field" />
            </xs:sequence>
        </xs:complexType>
    </xs:element>

    <xs:complexType name="field"> 
        <xs:sequence> 
            <xs:element name="value" type="xs:string" /> 
        </xs:sequence> 
    </xs:complexType> 



    <xs:complexType name="composite-Field" > 
        <xs:complexContent> 
            <xs:extension base="field" > 
                <xs:sequence> 
                    <xs:element name="length" type="xs:integer" /> 
                </xs:sequence> 
            </xs:extension> 
        </xs:complexContent> 
    </xs:complexType> 

    <xs:element name="MyCompositeField" type="composite-Field"/> 

</xs:schema>

所需的 xml 如下所示：

<?xml version="1.0" encoding="UTF-8"?>
 <general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField> 
        <value>enjoy</value> 
        <length>30</length> 
    </MyCompositeField> 

 </general>

使用此组合，我得到响应错误消息：

cvc-complex-type.2.4.a：无效找到的内容始于元素“MyCompositeField”。之一应为“{field}”。

原文

I defined xml schema the contains an element called 'field' and an extension to it called 'composite-field'.
it is defined as following:

<xs:complexType name="field">
        <xs:sequence>
            <xs:element name="value" type="xs:string" />
        </xs:sequence>      
</xs:complexType>
<xs:complexType name="composite-Field">
        <xs:complexContent>
          <xs:extension base="field">
            <xs:sequence>
                    <xs:element name="length" type="xs:integer" />
                  </xs:sequence>
                </xs:extension>
        </xs:complexContent>
</xs:complexType>

in order to use it in my XML ut has to be:

<field xsi:type="composite-Field">
  <value>enjoy</value>
  <length>30</length>
</field>

I don't want my XML users to use schema syntax such as xsi:type=..." "
Therefore my question is: Is there any way to make the syntax of the XML be:

<composite-Field>
      <value>enjoy</value>
      <length>30</length>
</composite-Field>

so the name of the element will imply its inheritence and wouldn't force the users add type attribute ??

I tried this:

<xs:element name="MyCompositeField" type="composite-field"/>

and then:

<MyCompositeField>
          <value>enjoy</value>
          <length>30</length>
</MyCompositeField>

but it also didn't pass the XSD schema validation

12/09/2010: In response the suggested answer I refined my question a liitle bit.
The schema looks like that:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 

    <xs:element name="general">
        <xs:complexType>
            <xs:sequence>
                <xs:element name="field" type="field" />
            </xs:sequence>
        </xs:complexType>
    </xs:element>

    <xs:complexType name="field"> 
        <xs:sequence> 
            <xs:element name="value" type="xs:string" /> 
        </xs:sequence> 
    </xs:complexType> 



    <xs:complexType name="composite-Field" > 
        <xs:complexContent> 
            <xs:extension base="field" > 
                <xs:sequence> 
                    <xs:element name="length" type="xs:integer" /> 
                </xs:sequence> 
            </xs:extension> 
        </xs:complexContent> 
    </xs:complexType> 

    <xs:element name="MyCompositeField" type="composite-Field"/> 

</xs:schema>

and the required xml looks like that:

<?xml version="1.0" encoding="UTF-8"?>
 <general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField> 
        <value>enjoy</value> 
        <length>30</length> 
    </MyCompositeField> 

 </general>

using this combination I get in response the error message:

cvc-complex-type.2.4.a: Invalid
content was found starting with
element 'MyCompositeField'. One of
'{field}' is expected.

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娇俏 2024-09-25 05:14:01

您的问题更新表明真正的问题在于元素。有效的文档将

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

扩展类型“字段”不会修改原始类型。相反，它创建了一个基于旧“字段”类型的新类型。如果您想将和元素作为元素的子元素，则应该更改元素的类型从“field”到“composite-Field”。

<xs:element name="general">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="field" type="composite-Field" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

这将验证文档

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
        <length>30</length> 
    </field> 
</general>

其他解决方案是更改元素的子元素而不是元素因为已经具有内容类型“composite-Field”，

<xs:element name="general">
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="MyCompositeField" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

这将验证文档

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField>
        <value>enjoy</value>
        <length>30</length>
    </MyCompositeField>
</general>

更新 2010-08-14

原发帖者评论：

但我希望“常规”元素能够包含“字段”或“复合字段”。不要严格要求只有其中一种类型。

那么您真正的问题是您希望您的模式验证这两个文档吗？

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

在这种情况下，

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField>
        <value>enjoy</value>
        <length>30</length>
    </MyCompositeField>
</general>

整个问题可以看作：

“如何允许元素将这些选择之一作为子元素？”
或者因为您的类型几乎相似：
“如何允许可选元素（可以不存在的元素）？”

如果您最初明确说明您想要实现的目标/代码是什么以及您当前拥有哪些代码会导致您的问题，那么整个问题可能会更快地得到解决

回答 #1 使用 < code>以允许多个独立子内容之一。

使用此结构，您可以允许具有或子元素，

<xs:element name="general">
    <xs:complexType>
        <xs:choice>
            <xs:element name="field" type="field" />
            <xs:element name="MyCompositeField" type="composite-Field" />
        </xs:choice>
    </xs:complexType>
</xs:element>

因此您的此更改架构将允许我上面发布的两个文档。

回答 #2 如果使用 composite-Field 类型的唯一原因是允许可选的元素，您可以轻松修改原始 field 类型并使用它代替类型 composite-Field

<xs:complexType name="field"> 
    <xs:sequence> 
        <xs:element name="value" type="xs:string" /> 
        <xs:element name="length" type="xs:integer" minOccurs="0" /> 
    </xs:sequence> 
</xs:complexType>

此架构定义创建一个允许可选长度元素的类型，从而验证这两个文档

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

和

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
        <length>30</length> 
    </field> 
</general>

Your question update shows that the real problem is in the <general> element. A valid document would be

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

Extending the type "field" does not modify the original type. Instead it creates a new type that is based on the old "field" type. If you wanted to have both <value> and <length> elements as the chlidren of <field> element, you should change the type of the <field> element from "field" to "composite-Field".

<xs:element name="general">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="field" type="composite-Field" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

This validates document

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
        <length>30</length> 
    </field> 
</general>

Other solution would be to change the <general> element have child element <MyCompositeField> instead of element <field> since <MyCompositeField> already has content type "composite-Field"

<xs:element name="general">
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="MyCompositeField" />
        </xs:sequence>
    </xs:complexType>
</xs:element>

which would validate document

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField>
        <value>enjoy</value>
        <length>30</length>
    </MyCompositeField>
</general>

Update 2010-08-14

Comment by original poster:

But I want 'general' element to have the ability to contain either 'field' or 'composite-field'. Not to strict it to have ONLY one of those types.

So is your real problem is that you want your schema to validate both of these documents?

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

and

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <MyCompositeField>
        <value>enjoy</value>
        <length>30</length>
    </MyCompositeField>
</general>

In that case the whole question can be seen as:

"how to allow an element to have one of these choices as a child element?"
or because your types are almost similar:
"how to allow an optional element (element that can be absent)?"

The whole question could have been solved much faster if you had initially clearly stated what is your goal/code that you want to achieve and what code do you currently have that causes your problems

Answer to #1 Use <xs:choice> to allow one of several independent child contents.

With this structure you can allow <general> to have either <field> or <MyCompositeField> child element

<xs:element name="general">
    <xs:complexType>
        <xs:choice>
            <xs:element name="field" type="field" />
            <xs:element name="MyCompositeField" type="composite-Field" />
        </xs:choice>
    </xs:complexType>
</xs:element>

So this change in your schema would allow both of the documents I posted above.

Answer to #2 If the only reason to have type composite-Field is to allow an optional <length> element you could just easily modify the original field type and use it instead of type composite-Field

<xs:complexType name="field"> 
    <xs:sequence> 
        <xs:element name="value" type="xs:string" /> 
        <xs:element name="length" type="xs:integer" minOccurs="0" /> 
    </xs:sequence> 
</xs:complexType>

This schema definition creates a type that allows an optional length element and thus validates both of these documents

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
    </field> 
</general>

and

<?xml version="1.0" encoding="UTF-8"?>
<general xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="schema2.xsd">
    <field> 
        <value>enjoy</value> 
        <length>30</length> 
    </field> 
</general>

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