XSD 学习

===================XML==============
<ROOT>
 <ITEM>
  <A>ABC0000487</A>
  <B>ABCDEFGH</B>
  <C>DFEF</C> 
  .....
  </ITEM>
 </ROOT>
===================XSD================
<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="ITEMGSchema" elementFormDefault="qualified" xmlns="http://www.w3.org/2001/XMLSchema/ITEMGSchema.xsd" xmlns:mstns="http://www.w3.org/2001/XMLSchema/ITEMGSchema.xsd" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="ROOT">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="ITEM" maxOccurs="unbounded">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="A">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="50"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="B">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="8"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="C">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="18"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="D">
                <xs:simpleType>
                  <xs:restriction base="xs:integer">
                    <xs:pattern value="[1-9]" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="E">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="3"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="F">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:enumeration value="1" />
                    <xs:enumeration value="2" />
                    <xs:enumeration value="3" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="G">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="18"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="H">
                <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                    <xs:fractionDigits value="3" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="I">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:enumeration value="Y" />
                    <xs:enumeration value="N" />
                    <xs:enumeration value="T" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="J">
                <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                    <xs:fractionDigits value="3" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="K">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="3"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="L">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="4"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="M">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="50"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="N">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="10"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="O">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="5"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="P">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="10"/>
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
              <xs:element name="Q">
                <xs:simpleType>
                  <xs:restriction base="xs:string">
                    <xs:maxLength value="6" />
                  </xs:restriction>
                </xs:simpleType>
              </xs:element>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>