大虾请指教DTD具体怎么理解

[ladofwind]

大虾请指教DTD具体怎么理解,写出一个具体对应此DTD的XML，谢谢

<?xml version="1.0" encoding="UTF-8" ?>
<!ELEMENT Field EMPTY >
<!ATTLIST Field Width NMTOKEN #IMPLIED >
<!ATTLIST Field Name NMTOKEN #REQUIRED >
<!ATTLIST Field Type ( date | enum | text ) #REQUIRED >
<!ATTLIST Field Enums CDATA #REQUIRED >
<!ATTLIST Field Desc NMTOKEN #REQUIRED >

<!ELEMENT DataSources ( DataSource+ ) >

<!ELEMENT DataSource ( Field+ ) >
<!ATTLIST DataSource IsStastics NMTOKEN #IMPLIED >
<!ATTLIST DataSource Name NMTOKEN #REQUIRED >
<!ATTLIST DataSource ID NMTOKEN #REQUIRED >
<!ATTLIST DataSource ForeignKey CDATA #REQUIRED >
<!ATTLIST DataSource TableName CDATA #REQUIRED >
<!ATTLIST DataSource CategoryID CDATA #REQUIRED >
<!ATTLIST DataSource SearchType NMTOKEN #REQUIRED >

[infowain]

http://www.cnw.com.cn/issues/2000/45/4514a.asp
http://www.cnw.com.cn/issues/2000/47/4714a.asp