Question

Write a DTD for this XML document such that the corrected version of the example is a valid XML document

<?xml version="1.0"?>

<computers>

<item type = "Laptop" code = "Dell437">

   <make>

   <brand>Dell Inspiration</Brand>

   <supplier id = "Dell"/>

   </make>

   <spec>

   <cpu speed = "900"/>

   <harddisk size = "12" units = "GB"/>

   </Spec>

   <price n = "950" units = "USD"/>

</item>

<item type = "Desktop" code = "Apple1679">

   <make>

   <brand>Apple iMac</brand>

   <supplier id = "Apple"/>

   <make>

   <spec>

   <cpu speed = "1100"/>

   <harddisk size = "16" units = "GB"/>

   </spec>

   <price n = "790" units = "USD"/>

</item>

</computers>

Answer 1

Given XML code has errors, below is the updated code.

<?xml version="1.0"?>
<computers>
        <item type = "Laptop" code = "Dell437">
           <make>
                   <brand>Dell Inspiration</brand>
                   <supplier id = "Dell"/>
           </make>
           <spec>
                   <cpu speed = "900"/>
                   <harddisk size = "12" units = "GB"/>
           </spec>
           <price n = "950" units = "USD"/>
        </item>
        <item type = "Desktop" code = "Apple1679">
           <make>
                   <brand>Apple iMac</brand>
                   <supplier id = "Apple"/>
           </make>
           <spec>
                   <cpu speed = "1100"/>
                   <harddisk size = "16" units = "GB"/>
           </spec>
           <price n = "790" units = "USD"/>
        </item>
</computers>

DTD :

<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="computers">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="item" maxOccurs="unbounded" minOccurs="0">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="make">
                <xs:complexType>
                  <xs:sequence>
                    <xs:element type="xs:string" name="brand"/>
                    <xs:element name="supplier">
                      <xs:complexType>
                        <xs:simpleContent>
                          <xs:extension base="xs:string">
                            <xs:attribute type="xs:string" name="id" use="optional"/>
                          </xs:extension>
                        </xs:simpleContent>
                      </xs:complexType>
                    </xs:element>
                  </xs:sequence>
                </xs:complexType>
              </xs:element>
              <xs:element name="spec">
                <xs:complexType>
                  <xs:sequence>
                    <xs:element name="cpu">
                      <xs:complexType>
                        <xs:simpleContent>
                          <xs:extension base="xs:string">
                            <xs:attribute type="xs:short" name="speed" use="optional"/>
                          </xs:extension>
                        </xs:simpleContent>
                      </xs:complexType>
                    </xs:element>
                    <xs:element name="harddisk">
                      <xs:complexType>
                        <xs:simpleContent>
                          <xs:extension base="xs:string">
                            <xs:attribute type="xs:byte" name="size" use="optional"/>
                            <xs:attribute type="xs:string" name="units" use="optional"/>
                          </xs:extension>
                        </xs:simpleContent>
                      </xs:complexType>
                    </xs:element>
                  </xs:sequence>
                </xs:complexType>
              </xs:element>
              <xs:element name="price">
                <xs:complexType>
                  <xs:simpleContent>
                    <xs:extension base="xs:string">
                      <xs:attribute type="xs:short" name="n" use="optional"/>
                      <xs:attribute type="xs:string" name="units" use="optional"/>
                    </xs:extension>
                  </xs:simpleContent>
                </xs:complexType>
              </xs:element>
            </xs:sequence>
            <xs:attribute type="xs:string" name="type" use="optional"/>
            <xs:attribute type="xs:string" name="code" use="optional"/>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

Screenshots :