Question

好的，所以我需要为XML项目声明名称空间，并使用DTD进行验证。一切似乎都是正确的，甚至我的朋友和教授都这么说，但我不断收到一条错误消息，说“元素”st：course“的前缀”st“没有约束。”它看起来与我有关，我错过了什么？

XML：

<?xml-namespace ns="http://www.student_courses/data/st/ns" prefix="st"?>
<?xml-namespace ns="http://www.student_courses/data/cr/ns" prefix="cr"?>
<!DOCTYPE students SYSTEM "student_courses.dtd">

<students>
<student number="a101"> <!-- number is an ID, required-->
<Name title="Mr.">John Doe</Name><!-- title values can be 'Mr.','Ms.','Dr.'-->
<st:course xmlns= "http://www.student_courses/data/st/ns" section="01">WEB 225</st:course>
<enrolled>22</enrolled>

<content>
<level class="Intro"></level>
<comments>Great course</comments><!-- An optional element -->
<book isbn="">XML</book><!--isbn is required, but the element is optional -->
</content>
</student>

<student number="a102"><!-- number is an ID, required-->
<Name title="Dr.">Jane Williams</Name>
<st:course xmlns= "http://www.student_courses/data/st/ns">WEB 325</st:course>
<enrolled>22</enrolled>

<content>
<level class="Adv."></level>
</content>
</student>

<student number="a103"><!-- number is an ID, required-->
<Name title="Ms.">Jane Doe</Name><!-- title values can be 'Mr.','Ms.','Dr.'-->
<st:course xmlns= "http://www.student_courses/data/st/ns" section="03">WEB  440</st:course>
<enrolled>12</enrolled>

<content>
<level class="Adv."></level>
<comments>Great course</comments><!-- An optional element -->
</content>
</student>

<courses>

<cr:course xmlns = "http://www.student_courses/data/cr/ns" id="WEB225">
<name>Web Development II</name>
<offered>Spring</offered>
<pre_reqs>WEB125</pre_reqs>
</cr:course>

<cr:course xmlns = "http://www.student_courses/data/cr/ns" id="WEB125">
<name>Web Development I</name>
<offered>Fall</offered>
</cr:course>

<cr:course xmlns = "http://www.student_courses/data/cr/ns" id="WEB325">
<name>Client-Side Scripting</name>
<offered>Spring</offered>
<offered>Fall</offered>
<pre_reqs>WEB225</pre_reqs>
</cr:course>

</courses>

</students>

这是我的DTD：

<!ELEMENT students (student+)>
<!ELEMENT student (Name+,st:course+,enrolled+,content+)>
<!ATTLIST student number ID #REQUIRED>
<!ELEMENT Name (#PCDATA)>
<!ATTLIST Name title (Mr. | Ms. | Dr.) #IMPLIED>
<!ELEMENT st:course (#PCDATA)>
<!ATTLIST st:course xmlns CDATA #FIXED "http://www.student_courses/data/st/ns"> 
<!ATTLIST st:course section CDATA #IMPLIED>
<!ELEMENT enrolled (#PCDATA)>
<!ELEMENT content (level+, comments*, book?)>
<!ELEMENT level (#PCDATA)>
<!ATTLIST level class (Intro | Adv.) #IMPLIED>
<!ELEMENT comments (#PCDATA)> 
<!ELEMENT book (#PCDATA)>
<!ATTLIST book isbn CDATA #REQUIRED>
<!ELEMENT courses (cr:course+)>
<!ELEMENT cr:course (name+,offered+,pre_reqs*)>
<!ATTLIST cr:course xmlns:cr CDATA #FIXED "http://www.student_courses/data/cr/ns"> 
<!ATTLIST cr:course id CDATA #REQUIRED>
<!ELEMENT name (#PCDATA)>
<!ELEMENT offered (#PCDATA)>
<!ELEMENT pre_reqs (#PCDATA)>

谢谢大家，爱这个地方!!

-K

Answer 1

你的问题是：

在DTD更改＆lt;！ATTLIST st：course xmlns CDATA #FIXED“http://www.student_courses/data/st/ns”＆gt; to＆lt;！ATTLIST st：course xmlns：st CDATA #FIXED“http://www.student_courses/data/st/ns”＆gt;
在XML中评论您的＆lt; courses＆gt; ...＆lt; / courses＆gt;元素，因为它根据您的DTD无效。您的DTD已经＆lt; student＆gt;在＆lt; students＆gt;下仅
随处更改XML＆lt; st：course xmlns =“http://www.student_courses/data/st/ns”...＆gt; to＆lt; st：course xmlns：st =“http：//www.student_courses/data/st/ns”...＆gt;
在XML更改开始时＆lt;？xml-namespace ns =“http：//www.student_courses/data/st/ns"prefix =”st“？＆gt; to＆lt;？xml-namespace st =“http：//www.student_courses/data/st/ns”prefix =“st”？＆gt;

第一个和第三个是相互核心的。如果你想把你的'course'元素保持为'st：course'（带名称空间前缀），那么你必须将它保存到你的DTD中。

第二和第三是自我解释。

XML DTD命名空间未绑定

1 个答案: