xml dtd schema基础

<?xml version="1.0" standalone='yes'?>
     <!DOCTYPE people [
     <!ELEMENT people (person+)>
     <!ELEMENT person (#PCDATA)>
     ]>

<!ELEMENT people (person+)>
<!ELEMENT person (name, look*, possession?, other?)>
<!ELEMENT name (firstname, lastname)>
<!ELEMENT firstname (#PCDATA)>
<!ELEMENT lastname (#PCDATA)>
<!ELEMENT look (#PCDATA)>
<!ELEMENT possession (car?, house?, bankaccount?, job?)>
<!ELEMENT car (#PCDATA|model)*>
<!ELEMENT model (#PCDATA)>
<!ELEMENT house (apartment|standalone|townhouse)>
<!ATTLIST house house_area ID #IMPLIED country CDATA #FIXED 
"CANADA" city CDATA #IMPLIED>
<!ELEMENT apartment EMPTY>
<!ELEMENT standalone EMPTY>
<!ELEMENT townhouse EMPTY>
<!ATTLIST townhouse townhouse_type ID #IMPLIED>
<!ELEMENT bankaccount (#PCDATA)>
<!ATTLIST bankaccount bankaccount_number ID #REQUIRED>
<!ELEMENT job (#PCDATA)>
<!ELEMENT other ANY>
<!ENTITY IBM "Proud to work for IBM">

http://www.ibm.com/developerworks/cn/xml/x-dtdint/#resources
http://www.w3school.com.cn/schema/schema_intro.asp
http://wenku.baidu.com/view/6a4ae90c844769eae009ed9f.html
http://www.w3school.com.cn/xml/xml_namespaces.asp