05_dtd

<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT classromm (className,grade,students+)>
<!ATTLIST classromm id ID #REQUIRED>
<!ELEMENT className (#PCDATA)>
<!ELEMENT grade (#PCDATA)>
<!ELEMENT students (student+)>
<!ELEMENT student (id,stuName,age)>
<!ELEMENT id (#PCDATA)>
<!ELEMENT stuName (#PCDATA)>
<!ELEMENT age (#PCDATA)>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE classrom SYSTEM "classroom.dtd">
<classrom id="c1">
    <className>14bling</className>
    <grade>2014</grade>
    <students>
        <student>
            <id>1</id>
            <stuName>bling</stuName>
            <age>23</age>
        </student>
        <student>
            <id>2</id>
            <stuName>jun</stuName>
            <age>20</age>
        </student>
    </students>
</classrom>