Question:
(a) Explain the five different types of element content defined by DTDs.
(b) Compare XML schema's against DTDs.
(c) Consider the following two element declarations from an XML DTD:
where all elements not declared are assumed to have content models of #PCDATA.
(i) Assume that the information about the isbn of a book is to be represented as an attribute rather than an element.
Write down an appropriate attribute declaration for an isbn attribute.
(ii) Write an XPath expression to find books that have more than 2 authors.
(iii) Write down an XML document of type book that is valid with respect to the above DTD using the fewest number of elements possible.