Discuss: What did you think of the different data flow diagrams levels and what they represent? How do you think they could be improved? What software did you use to draw data flow diagrams?

Answer the following questions:

1.Distinguish between logical process models and physical process models.

2. Define what is meant by a process in a process model. How should the process be named? What information about a process should be stored in the CASE repository?

3. Define what is meant by a data flow in a process model. How should the data flow be named? What information about a data flow should be stored in the CASE repository?

4. Define what is meant by a data store in a process model. How should the data store be named? What information about a data store should be stored in the CASE repository?

Answer the following:

Draw a level 0 data flow diagram (DFD) for a university library system. The system records all books owned by the library and the information of who borrows the books. For students to borrow a book, a valid ID is required. The validity of the ID is checked against the registrars office database. Faculty and staff must show an ID as well. The validity of their ID is checked against the university human resources database. The library has a separate database for other guests. The library system will also ensure that the borrower does not have any overdue books or unpaid fines. The library issues an email/mail notice once a week to all borrowers with books overdue for a week, and issue a fine if a book if overdue for more than two weeks. Finally, when a book is lost or damaged, the book is removed from the library database.