XML Schema groupElement


XML Schema 参考手册Complete XML Schema Reference Manual

Definition and Usage

The group element is used to define groups of elements used in complex type definitions.

Element Information

  • Parent element: schema, choice, sequence, complexType, restriction (both simpleContent and complexContent), extension (both simpleContent and complexContent)

Syntax

<group
id=ID
name=NCName
ref=QName
maxOccurs=nonNegativeInteger|unbounded
minOccurs=nonNegativeInteger
any attributes
>

(annotation?,(all|choice|sequence)?)

</group>

(The ? sign declares that the group element can occur zero or one time.)

Attributes Description
id Optional. Specifies a unique ID for the element.
name

Optional. Specifies the name of the group. This name must be a no-colon name (NCName) defined in the XML Namespace specification.

Use this attribute only when the schema element is the parent of the group element. In this case, the group is a model group used by complexType, choice, and sequence elements.

The name attribute and the ref attribute cannot appear at the same time.

ref

Optional. References the name of another group. The ref value must be a QName. The ref can contain a namespace prefix.

The name attribute and the ref attribute cannot appear at the same time.

maxOccurs

Optional. Specifies the maximum number of times the group element can appear in the parent element. This value can be an integer greater than or equal to zero. To set no limit on the maximum number, use the string "unbounded". The default value is 1.

minOccurs

Optional. Specifies the minimum number of times the group element can appear in the parent element. This value can be an integer greater than or equal to zero. The default value is 1.

any attributes

Optional. Specifies any other attributes with a non-schema namespace.

Example 1

The following example defines a group containing a sequence of four elements, and uses this group element in a complex type definition:

<?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>


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