Declaring an attribute

Declaring an attribute

A simple element can not contain attributes, if an element contains attributes item it is considered as complex type.

Syntax:

      <xs: attribute name=”xxx” type=”yyy” />

Declaring an attribute with a fixed value

Syntax: <xs: attribute name=”xxx” type=”yyy” fixed=”value”/>

Declaring an attribute that is:  either optional (or) mandatory:

Syntax:

<xs: attribute name=”xxx” type=”yyy” use=”optional/required”/>

Restrictions:

To allow the user to type acceptable value for the XML elements. The restrictions on XML elements are called as facets.

What is a facet?

It allows the users to type acceptable value for the XML elements. These restrictions on XML elements are called facets.

Restrictions on range of values:

Syntax:

<xs: element name=”xxx”>

      <xs: simpleType>

         <xs: restriction base=”yyy”>

            <xs: mininclusive value=”minvalue”/>

            <xs: maxinclusive value=”maxvalue”/>

         </xs: restriction>

      </xs:simpleType>

</xs: element>

·         Instead of mininclusive and maxinclusive we can write minExclusive and MaxExclusive.

·         We can combine also

·         In minInclusive and MaxInclusive we can include the extreme values where as in MinExclusive and MaxExclusive, we can not include extreme values.

Restrictions on List of values:

<xs: element name=”xxx”>

  <xs: simpleType>

     <xs:restriction base=”yyy”>

         <xs:enumeration value=”value1”/>

      <xs: enumeration value=”value2”/>

      <xs: enumeration value=”value3”/>

    </xs: restriction>

  </xs: simpleType>

</xs: element>

Patterns:

Syntax:

 <xs: element name=”xxx”>

  <xs: simpleType>

    <xs:restriction base=”yyy”>

     <xs: pattern value=”[a..z],[a-z]”/>

   </xs: restriction>

</xs:simpleType>

</xs:element>

·        

The above pattern indicating the length of the data to be three characters and the characters must be only lower case alphabets.

Patterns2:

<xs: pattern value=”[a-zA-Z][a-Za-z]”/>

·         The above pattern indicates that the data must contain two characters and the characters can be either lower case alphabets or uppercase alphabets.

Patterns3:

<xs: pattern value=”[aeiou]”/>

·         The above pattern indicates the data can contain only one character among a,e,I,o,u

Pattern4:

<xs: pattern value=”[0-9][0-9]”/>

·         The above pattern indicates that data should contain exactly two digits.

Pattern5:

<xs:pattern value=”([a-z])*”/>

·         The above pattern indicates that data can contain 0 or more characters and the characters should be only lower case alphabets.

Pattern6:

<xs: pattern value=”([a-z][A-Z])+”/>

·         The above pattern indicates that data can contain even number of characters and it should contain min/max two characters out of which the first one is lower case alphabet the second one is upper case alphabet

Pattern7:

 <xs: pattern value=”[0-9]{10}”/>

·         The above pattern indicates that the data must contain exactly ten(10) digits.