Specify a DTD appropriate for a document that contains data from both the Course table in Figure 4.34, and the Requires table in Figure 4.35. Try to re?ect as many constraints as the DTDs allow. Give an example of a document that conforms to your DTD.

What will be an ideal response?

One good example of such a document is shown below. Note that it does not try to mimic the relational representation, but instead courses are modeled using the object-oriented approach.





       
                      CrsName="Transaction Processing" CreditHours="3">

              

              

        

        

               .....

        

         .....

An appropriate DTD would be:




      

      


                        CrsCode ID #REQUIRED

                        DeptId CDATA #IMPLIED

                        CrsName CDATA #REQUIRED

                        CreditHours CDATA #REQUIRED >


                        CrsCode IDREF #REQUIRED

                        EnforcedSince CDATA #REQUIRED>