XML Schema restrictionElement

XML Schema 参考手册Complete XML Schema Reference Manual

Definition and Usage

The restriction element defines constraints on a simpleType, simpleContent, or complexContent definition.

Element Information

  • Parent elements: simpleType, simpleContent, complexContent

Syntax

<restriction
id=ID
base=QName
any attributes
>

Content for simpleType:
(annotation?,(simpleType?,(minExclusive|minInclusive|
maxExclusive|maxInclusive|totalDigits|fractionDigits|
length|minLength|maxLength|enumeration|whiteSpace|pattern)*))

Content for simpleContent:
(annotation?,(simpleType?,(minExclusive |minInclusive|
maxExclusive|maxInclusive|totalDigits|fractionDigits|
length|minLength|maxLength|enumeration|whiteSpace|pattern)*)?,
((attribute|attributeGroup)*,anyAttribute?))

Content for complexContent:
(annotation?,(group|all|choice|sequence)?,
((attribute|attributeGroup)*,anyAttribute?))

</restriction>

(The ? symbol declares that the element can occur zero or one time inside the restriction element.)

Attributes Description
id Optional. Specifies a unique ID for this element.
base Required. Specifies the name of a built-in data type, simpleType, or complexType element defined in this schema (or in another schema indicated by the specified namespace).
any attributes Optional. Specifies any other attributes with a non-schema namespace.

Example 1

The following example defines an element named "age" with a restriction. The value of age cannot be less than 0 or greater than 100:

<xs:element name="age">
  <xs:simpleType>
    <xs:restriction base="xs:integer">
      <xs:minInclusive value="0"/>
      <xs:maxInclusive value="100"/>
    </xs:restriction>
  </xs:simpleType>
</xs:element>

Example 2

This example defines an element named "initials". The "initials" element is a simple type with a restriction. The acceptable values are three uppercase or lowercase letters from a to z:

<xs:element name="initials">
  <xs:simpleType>
    <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z][a-zA-Z][a-zA-Z]"/>
    </xs:restriction>
  </xs:simpleType>
</xs:element>

Example 3

This example defines an element named "password". The "password" element is a simple type with a restriction. The value must be a minimum of 5 characters and a maximum of 8 characters:

<xs:element name="password">
  <xs:simpleType>
    <xs:restriction base="xs:string">
      <xs:minLength value="5"/>
      <xs:maxLength value="8"/>
    </xs:restriction>
  </xs:simpleType>
</xs:element>

Example 4

This example shows a complex type definition using a restriction. The complex type "Chinese_customer" is derived from a normal customer complex type, whose country element has a fixed value of "China":

<xs:complexType name="customer">
  <xs:sequence>
    <xs:element name="firstname" type="xs:string"/>
    <xs:element name="lastname" type="xs:string"/>
    <xs:element name="country" type="xs:string"/>
  </xs:sequence>
</xs:complexType>

<xs:complexType name="Norwegian_customer">
  <xs:complexContent>
    <xs:restriction base="customer">
      <xs:sequence>
        <xs:element name="firstname" type="xs:string"/>
        <xs:element name="lastname" type="xs:string"/>
        <xs:element name="country" type="xs:string" fixed="Norway"/>
      </xs:sequence>
    </xs:restriction>
  </xs:complexContent>
</xs:complexType>

XML Schema 参考手册Complete XML Schema Reference Manual Other Extensions