This document describes converting a DTD to an XML schema. It provides the DTD for an RSS feed and then the equivalent XML schema. Key elements of the RSS feed like 'rss', 'channel', 'item' are defined as elements in the schema. Data types and element structures are also defined, such as specifying that the 'channel' element contains a choice of other elements that can occur in any order.

1. Prepared By: Dr.Saranya K.G
Converting DTDs to XML Schemas
<!ELEMENT rss (channel)>
<!ATTLIST rss
version CDATA #REQUIRED> <!-- must be "0.91"> -->
<!ELEMENT channel (title | description | link | language | item+ | rating? | image? |
textinput? | copyright? | pubDate? | lastBuildDate? | docs? | managingEditor? |
webMaster? | skipHours? | skipDays?)*>
<!ELEMENT title (#PCDATA)>
<!ELEMENT description (#PCDATA)>
<!ELEMENT link (#PCDATA)>
<!ELEMENT image (title | url | link | width? | height? | description?)*>
<!ELEMENT url (#PCDATA)>
<!ELEMENT item (title | link | description)*>
<!ELEMENT textinput (title | description | name | link)*>
<!ELEMENT name (#PCDATA)>
<!ELEMENT rating (#PCDATA)>
<!ELEMENT language (#PCDATA)>
<!ELEMENT width (#PCDATA)>
<!ELEMENT height (#PCDATA)>
<!ELEMENT copyright (#PCDATA)>
<!ELEMENT pubDate (#PCDATA)>
<!ELEMENT lastBuildDate (#PCDATA)>
<!ELEMENT docs (#PCDATA)>
<!ELEMENT managingEditor (#PCDATA)>
<!ELEMENT webMaster (#PCDATA)>
<!ELEMENT hour (#PCDATA)>
<!ELEMENT day (#PCDATA)>
<!ELEMENT skipHours (hour+)>
<!ELEMENT skipDays (day+)>

2. Prepared By: Dr.Saranya K.G
<schema
xmlns='http://www.w3.org/1999/XMLSchema'
targetNamespace='http://purl.org/rss/0.91'
xmlns:rss='http://purl.org/rss/0.91'>
<element name='rss'>
<complexType content='elementOnly'>
<element ref='rss:channel'/>
<attribute name='version' type='string' use='required'/>
</complexType>
</element>
<element name='channel'>
<complexType content='elementOnly'>
<choice minOccurs='0' maxOccurs='unbounded'>
<element ref='rss:title'/>
<element ref='rss:description'/>
<element ref='rss:link'/>
<element ref='rss:language'/>
<element ref='rss:item'/>
<element ref='rss:+'/>
<element ref='rss:rating'/>
<element ref='rss:?'/>
<element ref='rss:image'/>
<element ref='rss:?'/>
<element ref='rss:textinput'/>
<element ref='rss:?'/>
<element ref='rss:copyright'/>
<element ref='rss:?'/>
<element ref='rss:pubDate'/>
<element ref='rss:?'/>
<element ref='rss:lastBuildDate'/>
<element ref='rss:?'/>
<element ref='rss:docs'/>
<element ref='rss:?'/>
<element ref='rss:managingEditor'/>
<element ref='rss:?'/>
<element ref='rss:webMaster'/>
<element ref='rss:?'/>
<element ref='rss:skipHours'/>
<element ref='rss:?'/>
<element ref='rss:skipDays'/>
<element ref='rss:?'/>
</choice>
</complexType>

3. Prepared By: Dr.Saranya K.G
</element>
<element name='title'>
<complexType content='mixed'>
</complexType>
</element>
<element name='description'>
<complexType content='mixed'>
</complexType>
</element>
<element name='link'>
<complexType content='mixed'>
</complexType>
</element>
<element name='image'>
<complexType content='elementOnly'>
<choice minOccurs='0' maxOccurs='unbounded'>
<element ref='rss:title'/>
<element ref='rss:url'/>
<element ref='rss:link'/>
<element ref='rss:width'/>
<element ref='rss:?'/>
<element ref='rss:height'/>
<element ref='rss:?'/>
<element ref='rss:description'/>
<element ref='rss:?'/>
</choice>
</complexType>
</element>
<element name='url'>
<complexType content='mixed'>
</complexType>
</element>
<element name='item'>
<complexType content='elementOnly'>
<choice minOccurs='0' maxOccurs='unbounded'>
<element ref='rss:title'/>
<element ref='rss:link'/>
<element ref='rss:description'/>
</choice>
</complexType>

4. Prepared By: Dr.Saranya K.G
</element>
<element name='textinput'>
<complexType content='elementOnly'>
<choice minOccurs='0' maxOccurs='unbounded'>
<element ref='rss:title'/>
<element ref='rss:description'/>
<element ref='rss:name'/>
<element ref='rss:link'/>
</choice>
</complexType>
</element>
<element name='name'>
<complexType content='mixed'>
</complexType>
</element>
<element name='rating'>
<complexType content='mixed'>
</complexType>
</element>
<element name='language'>
<complexType content='mixed'>
</complexType>
</element>
<element name='width'>
<complexType content='mixed'>
</complexType>
</element>
<element name='height'>
<complexType content='mixed'>
</complexType>
</element>
<element name='copyright'>
<complexType content='mixed'>
</complexType>
</element>
<element name='pubDate'>
<complexType content='mixed'>
</complexType>

5. Prepared By: Dr.Saranya K.G
</element>
<element name='lastBuildDate'>
<complexType content='mixed'>
</complexType>
</element>
<element name='docs'>
<complexType content='mixed'>
</complexType>
</element>
<element name='managingEditor'>
<complexType content='mixed'>
</complexType>
</element>
<element name='webMaster'>
<complexType content='mixed'>
</complexType>
</element>
<element name='hour'>
<complexType content='mixed'>
</complexType>
</element>
<element name='day'>
<complexType content='mixed'>
</complexType>
</element>
<element name='skipHours'>
<complexType content='elementOnly'>
<element ref='rss:hour' maxOccurs='unbounded'/>
</complexType>
</element>
<element name='skipDays'>
<complexType content='elementOnly'>
<element ref='rss:day' maxOccurs='unbounded'/>
</complexType>
</element>
</schema>

6. Prepared By: Dr.Saranya K.G
Sample DTD
<!ELEMENT root (foo|(bar,baz)+)*>
<!ATTLIST root version CDATA #FIXED '1.0'>
<!ELEMENT foo EMPTY>
<!ELEMENT bar (#PCDATA)>
<!ELEMENT baz (#PCDATA|mumble)*>
<!ELEMENT mumble ANY>
XML Schema grammar:
<?xml version="1.0" encoding="UTF-8" ?>
<!-- Generated from data/dtd/test.dtd -->
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<!-- <!ELEMENT root (foo|(bar,baz)+)*> -->
<xsd:element name="root">
<xsd:complexType>
<xsd:choice minOccurs="0" maxOccurs="unbounded">
<xsd:element ref="foo" />
<xsd:sequence minOccurs="1" maxOccurs="unbounded">
<xsd:element ref="bar" />
<xsd:element ref="baz" />
</xsd:sequence>
</xsd:choice>
<!-- <!ATTLIST root version CDATA #FIXED "1.0"> -->
<xsd:attribute name="version" fixed="1.0">
<xsd:simpleType>
<xsd:restriction base="xsd:string" />

7. Prepared By: Dr.Saranya K.G
</xsd:simpleType>
</xsd:attribute>
</xsd:complexType>
</xsd:element>
...
</xsd:schema>