lesson4:XSD Restrictions

msi_333 · **Posted:** Wed Feb 25, 2009 12:38 am

To put restrictions on the XML element values or XML attributes.XML elements restriction are called Facets.
1. Enumerations :
Only allow a set of values for your XML element.

Code:

 <xs:element name="CustomColors">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:enumeration value="Red"/>
    <xs:enumeration value="Blue"/>
    <xs:enumeration value="Black"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

CustomColors values must have a value of these, (Red, Blue, & Black).

2. Patterns :
You limit your value to a series of letters and numbers .For example is the UUID.

Example on small letters patterns XSD element:

Code:

<xs:element name="small_letters">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:pattern value="[a-z]"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

Example on numbers only XSD element:

Code:

<xs:element name="numbers_only">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:pattern value="[0-9]"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

Universally Unique Identifier (UUID) XSD example:

Code:

     <element name="UUID" minOccurs="1">
               <simpleType>
                  <restriction base="ID">
                     <pattern
                        value="[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}">
                     </pattern>
                  </restriction>
               </simpleType>
            </element>

3. Numbers Range :
You can define the value range of an element. In the following example, the colorindex element can take value between (0-120).

Code:

<xs:element name="colorindex">
<xs:simpleType>
  <xs:restriction base="xs:integer">
    <xs:minInclusive value="0"/>
    <xs:maxInclusive value="120"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

4. Whitespaces :

You can leave the white spaces with no changes. preserve means no change.

Code:

<xs:element name="StudentName">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:whiteSpace value="preserve"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

You can use â€œreplaceâ€ value instead of â€œpreserveâ€ .This replace all space characters like (tabs ,line feeds ,and carriage return )with spaces.

Code:

<xs:element name="StudentName">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:whiteSpace value="replace"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 
 

You can use â€œcollapseâ€ to remove large spaces to one space.

Code:

<xs:element name="StudentName">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:whiteSpace value="collapse
"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

5. Values lengths:
You can set the length of element value; your value must equal the length restriction.

Code:

<xs:element name="username">
<xs:simpleType>
  <xs:restriction base="xs:string">
    <xs:length value="8"/>
  </xs:restriction>
</xs:simpleType>
</xs:element> 

You can define It with other way, minLength and manLength values.

Code:

<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> 

lesson4:XSD Restrictions

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