More DFDs

1. More DFDs Class 15

2. More examples • Projects, Inc. • Library Information System

3. Projects Inc. Projects, Inc. is an engineering firm with approximately 500 engineers of different types. New employees are hired by the personnel manager based on data in an application form and evaluations collected from other managers who interview the job candidates. Currently, Projects, Inc. has a manual interviewing system. The company would like to automate as much of the hiring and interviewing as possible.

4. The current system is as follows: Prospective employees may apply at any time by filling out an application which is kept on file by Projects, Inc. When a new job opens, engineering managers notify the personnel manager who creates a new file that describes the job and lists the characteristics necessary to be eligible for the job. The personnel manager compares the qualifications of the available pool of applicants with the characteristics of an open job, then schedules interviews between the manager in charge of the open position and the three best candidates from the pool. After receiving evaluations on each interview from the manager, the personnel manager makes the hiring decision based upon the evaluations and applications of the candidates and the characteristics of the job, and then notifies the applicant and the manager by phone. Applications of rejected applicants are retained for one year, after which time the application is purged. Currently, a clerk goes through the files each month to purge applications over one year old. When hired, a new engineer completes a nondisclosure agreement, which is filed with other information about the employee. Projects, Inc. would like you to automate the system. The processes that occur currently will still take place – everything will just be automated. Humans will still have to enter the information about applicants, employees, and jobs into the system, but the rest can be automated. Any phoning or notifying of people should now be done via a letter sent from the system.

5. Library Information System • Create a context level and zero level diagram for the system described on the next slide.

6. nThe University library system will record the books owned by the library as well as any new books purchased and put into circulation. Before someone can borrow a book, he or she must show a valid ID card that is checked – to ensure that it is still valid – against the student files maintained by the registrar’s office (for student borrowers), the faculty/staff files maintained by the personnel office (for faculty/staff borrowers), or the library’s own guest file (for individuals issued a guest card by the library). The system must also check to ensure the borrower does not have any overdue books or unpaid fines before he or she can borrow another book. If no fines or overdue books are found, the book is checked out. The system should record who has borrowed what book and when it is due back. The borrower is also told the due date. Books can only be checked out for two weeks. When a book is overdue, the information about the book and the person who checked it out is added to an overdue file. Every Monday, the library prints and mails postcards to those people with overdue books. If a book is overdue by more than one month, a fine will be imposed and a librarian will telephone the borrower to remind him or her to return the book.