DTD validation fails depending on format

[wesomon99]

I am using a DTD file to validate XML files. The format I would like to use defines an 'item' as:

<item item_idx="1" item_type="ExactNumber" content=".68" hint="Correlation does not equal causation."/>

However, this seems to fail to validate. It successfully validates if I define 'item' as:

<item>
        <item_idx>1</item_idx>
    <item_type>ExactNumber</item_type>
    <content>.68</content>
    <hint>Correlation does not equal causation</hint>
</item>

Do I need to define the DTD in a different way in order to use the first style? Or do I need to use a different XML schema?

Thanks for any help, below is the DTD file and the two examples in full.

DTD:
<!ELEMENT problem-set (problem+)>
<!ELEMENT problem (problem_idx, item+)>
<!ELEMENT problem_idx (#PCDATA)>
<!ELEMENT item (item_idx, item_type, content, hint)>
<!ELEMENT item_idx (#PCDATA)>
<!ELEMENT item_type (#PCDATA)>
<!ELEMENT content (#PCDATA)>
<!ELEMENT hint (#PCDATA)>

XMLExample1:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE problem-set SYSTEM "http://macalester.edu/~whart/XMLSchema.dtd">
<problem-set>
    <problem>
        <problem_idx>ProblemIndex1</problem_idx>
        <item>
            <item_idx>1</item_idx>
            <item_type>ExactNumber</item_type>
            <content>.68</content>
            <hint>Correlation does not equal causation</hint>
        </item>
        <item>
            <item_idx>2</item_idx>
            <item_type>ExactNumber</item_type>
            <content>.95</content>
            <hint>Causation equals correlation</hint>
        </item>
        <item>
            <item_idx>3</item_idx>
            <item_type>FreeText</item_type>
            <content></content>
            <hint>How much is a standard deviation?</hint>
        </item>
    </problem>
    <problem>
        <problem_idx>ProblemIndex2</problem_idx>
        <item>
            <item_idx>1</item_idx>
            <item_type>TrueOrFalse</item_type>
            <content>true</content>
            <hint>The truth lies in your mind.</hint>
        </item>
    </problem>
    <problem>
        <problem_idx>ProblemIndex3</problem_idx>
        <item>
            <item_idx>a</item_idx>
            <item_type>MC</item_type>
            <content>dublin</content>
            <hint>Think green</hint>
        </item>
    </problem>
</problem-set>

XMLExample2:

<?xml version="1.0" encoding="iso-8859-1"?>
    <problem-set>
        <problem>
            <problem_idx>ProblemIndex1</problem_idx>
            <item item_idx="1" item_type="ExactNumber" content=".68" hint="Correlation does not equal causation."></item>
            <item item_idx="2" item_type="ExactNumber" content=".95" hint="Causation equals correlation."></item>
            <item item_idx="3" item_type="FreeText" content="" hint="How much is a standard deviation?"></item>
        </problem>
        <problem>
            <problem_idx>ProblemIndex2</problem_idx>
            <item item_idx="1" item_type="TrueOrFalse" content="true" hint="The truth lies in your mind."></item>
        </problem>
        <problem>
            <problem_idx>ProblemIndex3</problem_idx>
            <item item_idx="a" item_type="MC" content="dublin" hint="Think green."></item>
        </problem>
    </problem-set>

[dorinbogdan]

Welcome to TheScripts TSDN...

Try this way:
<!ELEMENT problem-set (problem+)>
<!ELEMENT problem (problem_idx, item+)>
<!ELEMENT problem_idx (#PCDATA)>
<!ELEMENT item EMPTY>
<!ATTLIST item item_idx CDATA #REQUIRED>
<!ATTLIST item item_type CDATA #REQUIRED>
<!ATTLIST item content CDATA #REQUIRED>
<!ATTLIST item hint CDATA #REQUIRED>

For more help, see this link.

[wesomon99]

Ah okay, that makes sense. Thank you very much Dorin!

[dorinbogdan]

You're welcome.
God bless you,
Dorin.