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Worked out a use case diagram question from a past year paper. Would like some feedback on whether my diagram is correct based on the following question. Thanks for any guide.

Question: University new library system.

Students will use computer terminal to check availability of a book. Student library card is scanned into the system. System searches through the student database to check the student's borrowing history.

Student allowed to borrow a book subject to the following 2 constraints:

  • They have no overdue books
  • Currently no more than 4 books on loan.

If loan not permitted, the librarian can override the system and enter a code to allow the loan.

Student can borrow from another university's library by accessing inter-loan system to find to find book and place order. The above check of the student's card is again performed.

Special books within library cannot be borrowed. They can only be consulted. Also subjected to the 2 constrains previously described.

Finally, students have access to printer, using credits previously added by a 3rd party on his card. The card check for the printing process is subject to the constraints previously described.

Construct a UML representation of the processes described above. This will involve the production of one or more Use Case Diagrams.

Answer:

enter image description here

Link to my UML diagram: http://www.picpaste.com/pics/exam_uml-sCmMDwtm.1390472335.jpg

kar
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1 Answers1

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No. You shouldn't put any "if" logic into use case diagram. "No Overdue" or "Not >4books..." belong to more concrete diagrams - sequence, state, Activity, Interation Activity, maybe, Timing. But they are NOT use cases.

On the other hand, you have no system elements here. Use cases are subjects of dialogues between agents, that are people and system components or subsystems. You have only people here.

Also, you have no login activities here and no administrator. But maybe, it is out of the scope of the task.

Printer should be a subsystem. But you do not have "Print" use case connecting User and Printing Subsystem

Edit:

If you consider the checking so important to be present on the level of Use case diagram, create a subsystem for it and a use case or two between Actors and this subsystem.

And I see one more problem: interlib loan system and DB should appear as subsystems and access to the first and history check remain as use cased connected to them.

And I can't help with "consult special books", because I don't understand that at all.

And where are such base operations, as search for a book, search for the author, scan the card?

Notice, that your "includes" should become normal use cases between subsystems.

Gangnus
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  • Tnks for reply. As you can see I am supposed to be using use case diagram. So how can I fit in the check for overdue/ check for num.of bks on loan. For the printer, if I pull it out and place it as an actor and give it an association to the student plus give a use case 'print' to link to the printer, does it make sense then? – kar Jan 23 '14 at 16:56
  • If I may ask, how would you answer this question. Thanks. – kar Jan 23 '14 at 17:04
  • And one more point: If you'd be asked by your teacher to put something on some diagram WRONGLY, I wouldn't advice how to do it anyway. Very probably he wants you to struggle with it and find that it is inappropriate, yourself. – Gangnus Jan 24 '14 at 08:56