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The group element is used to define a group of elements to be used in complex type definitions.
group元素的作用是:定义一组在复合类型[complex type]中使用的元素。
<group id=ID name=NCName ref=QName maxOccurs=nonNegativeInteger|unbounded minOccurs=nonNegativeInteger any attributes > (annotation?,(all|choice|sequence)?) </group> |
(The ? sign declares that the element can occur zero or one time inside the group element)
“?”符号用于声明元素在group元素中允许出现的次数(0次或1次)
属性 | 描述 |
---|---|
id | Optional. Specifies a unique ID for the element 可选参数。为元素指定一个独立的ID |
name | Optional. Specifies a name for the group. This attribute is used only when the schema element is the parent of this group element. Name and ref attributes cannot both be present 可选参数。指定一个组名称。该属性仅当schema元素是group元素的父类元素时使用。该名称和ref 属性不能同时出现 |
ref | Optional. Refers to the name of another group. Name and ref attributes cannot both be present 可选参数。引用其它的组名称。该名称和ref 属性不能同时出现 |
maxOccurs | Optional. Specifies the maximum number of times the group element can occur in the parent element. The value can be any number >= 0, or if you want to set no limit on the maximum number, use the value "unbounded". Default value is 1 可选参数。指定group元素在父类元素中出现的最大次数。其值可以大于等于0;或者,如果你不希望对最大值进行限制,可以使用“unbounded”。默认值是1 |
minOccurs | Optional. Specifies the minimum number of times the group element can occur in the parent element. The value can be any number >= 0. Default value is 1 可选参数。指定group元素在父类元素中出现的最小次数。其值可以大于等于0。默认值是1 |
any attributes | Optional. Specifies any other attributes with non-schema namespace 可选参数。指定非schema命名空间的其它属性 |
The following example defines a group containing a sequence of four elements and uses the group element in a complex type definition:
下面的案例定义了一组包含4个元素的序列,并在一个复合类型定义中使用了group元素:
<?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:group name="custGroup"> <xs:sequence> <xs:element name="customer" type="xs:string"/> <xs:element name="orderdetails" type="xs:string"/> <xs:element name="billto" type="xs:string"/> <xs:element name="shipto" type="xs:string"/> </xs:sequence> </xs:group> <xs:element name="order" type="ordertype"/> <xs:complexType name="ordertype"> <xs:group ref="custGroup"/> <xs:attribute name="status" type="xs:string"/> </xs:complexType> </xs:schema> |