Xml Schema

[alwz_nikhil]

i have a xml file which look likes as follow

<StudentData>
    <student>
        <name>JOHN</name>
        <roll></roll>
        <address></address>
    </student>
    <student>
        <name></name>
        <roll></roll>
        <address></address>
    </student>
</StudentData>

wat i want is that every xml file which follows xsd must contain
these same set of tags.

        <name></name>
        <roll></roll>
        <address></address>
and there must be a student by name "JOHN"
    <student>
        <name>JOHN</name>
        <roll></roll>
        <address></address>
    </student>

can anyone help me out...
And any good tutrial on net about xsd creation ?

thanks

[Christy]

check www.w3schools.com its great