DTD AND XML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE trainlog[
<!ELEMENT trainlog (session+)>

 <!ELEMENT session (duration, distance, location, comments)>
  <!ATTLIST session
    date CDATA #IMPLIED
   type (running | swimming | cycling) "running"
   heartrate CDATA #IMPLIED>

 <!ELEMENT duration (#PCDATA)>
 <!ATTLIST duration
   units (seconds | minutes | hours) "minutes">

 <!ELEMENT distance (#PCDATA)>
 <!ATTLIST distance
   units (miles | kilometers | laps) "miles">

 <!ELEMENT location (#PCDATA)>

 <!ELEMENT comments (#PCDATA)>
 <!ENTITY WP "Warner Park">
 <!ENTITY  NTP "Natchez Trace Parkway">

]>
 <trainlog>
   <session date="11/19/05" type="running" heartrate="158">
     <duration units="minutes">50</duration>
     <distance units="miles">5.5</distance>
     <location>&WP;</location>
     <comments>Mid-morning run, a little winded throughout.</comments>
   </session>

   <session date="11/21/05" type="cycling" heartrate="153">
     <duration units="hours">1.5</duration>
     <distance units="miles">26.4</distance>
     <location>&NTP;</location>
     <comments>Hilly ride, felt strong as an ox.</comments>
   </session>
 </trainlog>