XML to DTD error: the document type declaration must be well-formed

Question

我是 XML 的初学者，我必须将以下 XML 转换为 DTD

<student id="12C042">

    <fName>John</fName>

    <lName>Nelson</lName>

    <plan>

        <courses year="3">

            <course>

                <name> Extensible Markup Language</name>

                <shortName>XML</shortName>

                <record>

                    <grade>30</grade>

                    <date>12-Jan-2017</date>

                </record>

            </course>

            <course>

                <name>Object Oriented Concepts and Unified Modeling Language</name>

                <shortName><![CDATA[OOP & UML]]></shortName>

            </course>

        </courses>

    </plan>

这是我转换后得到的DTD：

 <?xml encoding="UTF-8"?>

<!ELEMENT student (fName,lName,plan)>
<!ATTLIST student
  xmlns CDATA #FIXED ''
  id NMTOKEN #REQUIRED>

<!ELEMENT fName (#PCDATA)>
<!ATTLIST fName
  xmlns CDATA #FIXED ''>

<!ELEMENT lName (#PCDATA)>
<!ATTLIST lName
  xmlns CDATA #FIXED ''>

<!ELEMENT plan (courses)>
<!ATTLIST plan
  xmlns CDATA #FIXED ''>

<!ELEMENT courses (course)+>
<!ATTLIST courses
  xmlns CDATA #FIXED ''
  year CDATA #REQUIRED>

<!ELEMENT course (name,shortName,record?)>
<!ATTLIST course
  xmlns CDATA #FIXED ''>

<!ELEMENT name (#PCDATA)>
<!ATTLIST name
  xmlns CDATA #FIXED ''>

<!ELEMENT shortName (#PCDATA)>
<!ATTLIST shortName
  xmlns CDATA #FIXED ''>

<!ELEMENT record (grade,date)>
<!ATTLIST record
  xmlns CDATA #FIXED ''>

<!ELEMENT grade (#PCDATA)>
<!ATTLIST grade
  xmlns CDATA #FIXED ''>

<!ELEMENT date (#PCDATA)>
<!ATTLIST date
  xmlns CDATA #FIXED ''>

编译器给出以下错误：

致命错误：
Public ID: 空
系统ID：文件：/home/p12947/studentdtd.dtd
行号：9
列号：2
消息：文档类型包含或指向的标记声明 声明必须格式正确。
致命

Answer 1

尝试用 'student' 元素包围您的元素

根据您的 dtd 的有效文档可能如下所示

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE student SYSTEM "student.dtd">
<student id="1">
<fName>John</fName>
<lName>Nelson</lName>
<plan>
    <courses year="3">
        <course>
            <name> Extensible Markup Language</name>
            <shortName>XML</shortName>
            <record>
                <grade>30</grade>
                <date>12-Jan-2017</date>
            </record>
        </course>
        <course>
            <name>Object Oriented Concepts and Unified Modeling Language</name>
            <shortName><![CDATA[OOP & UML]]></shortName>
        </course>
    </courses>
</plan>
</student>

Answer 2

 <?xml version="1.0" encoding="UTF-8"?>
        <persons>
                  <person>
                        <name>XYZ</name>
                         <age>19</age>
                         <gender>M</gender>
                         <address>
                             <doorno>4</doorno>
                             <street>ABC</street>
                            <city>DEL</city>
                            <state>IND</state>
                       </address>
                        <student>
                            <rollno>34</rollno>
                            <standard>12</standard>
                            <section>C</section>
                         </student>
                 </person>
      </persons>