In addition, the enumeration markup allows binding of annotations to each item, whereas the pattern can only take a single annotation for the entire pattern.

In general, I would prefer the enumeration here because it is more granular.

This is from  schema I maintain as part of the DITA for Publishers project:

        <xs:simpleType>
          <xs:restriction
            base="xs:NMTOKEN">
            <xs:enumeration
              value="map">
              <xs:annotation>
                <xs:documentation>
                  <xhtml:div xmlns="http://www.w3.org/1999/xhtml">
                    <p>The paragraph maps to a map but not a map title.</p>
                  </xhtml:div>
                </xs:documentation>
              </xs:annotation>
            </xs:enumeration>
            <xs:enumeration
              value="mapTitle">
              <xs:annotation>
                <xs:documentation>
                  <xhtml:div xmlns="http://www.w3.org/1999/xhtml">
                    <p>The paragraph maps to the title of a map. Map titles are optional.</p>
                  </xhtml:div>
                </xs:documentation>
              </xs:annotation>
            </xs:enumeration>

           … many more values …

     </xs:restriction>

</xs:simpleType>

Cheers,

Eliot

Hi Folks,

Below are two XML Schema element declarations. Both enumerate a set of values for the <type> element. The first uses the pattern facet to enumerate the set of values. The second uses the enumeration facet. Is there a reason to prefer one over the other? Or, are they identical for all practical purposes?  /Roger

<xs:element name="type">
    <xs:simpleType>
        <xs:restriction base="xs:string">
            <xs:pattern value="contact|acquaintance|friend|met|co\-worker|colleague|co\-resident|neighbor|child|parent|sibling|spouse|kin|muse|crush|date|sweetheart|me|agent|emergency" />
        </xs:restriction>
    </xs:simpleType>
</xs:element>

<xs:element name="type">
    <xs:simpleType>
        <xs:restriction base="xs:string">
            <xs:enumeration value="contact" />
            <xs:enumeration value="acquaintance" />
            <xs:enumeration value="friend" />
            <xs:enumeration value="met" />
            <xs:enumeration value="co-worker" />
            <xs:enumeration value="colleague" />
            <xs:enumeration value="co-resident" />
            <xs:enumeration value="neighbor" />
            <xs:enumeration value="child" />
            <xs:enumeration value="parent" />
            <xs:enumeration value="sibling" />
            <xs:enumeration value="spouse" />
            <xs:enumeration value="kin" />
            <xs:enumeration value="muse" />
            <xs:enumeration value="crush" />
            <xs:enumeration value="date" />
            <xs:enumeration value="sweetheart" />
            <xs:enumeration value="me" />
            <xs:enumeration value="agent" />
            <xs:enumeration value="emergency" />
        </xs:restriction>
    </xs:simpleType>
</xs:element>