NOTE: I am self studying UML so I have nobody to verify my diagrams and hence I am posting here, so please bear with me. This is the problem I got from some PDF available on Google that simply had the following problem statement:
Problem Statement:
A library contains books and journals. The task is to develop a
computer system for borrowing books. In order to borrow a book
the borrower must be a member of the library. There is a limit on the
number of books that can be borrowed by each member of the library.
The library may have several copies of a given book.
It is possible to reserve a book.
Some books are for short term loans only. Other books may be
borrowed for 3 weeks. Users can extend the loans.
1. Draw a use case diagram for a library.
2. Give a use case description for two use cases:
• Borrow copy of book
• Extend loan
Diagram:
Use case description:
1. Borrow a copy of the book: If the person wishes to borrow a book from Derpville Public Library, he/she must be a member of the library in which case they will be allowed to issue a certain number of books. If the person is not a member, the book will not be issued to them for taking away, rather they will have to sit and read in the library.
2. Extending loan: Some books will be lent for 3 weeks while others will be lent for more than 3 weeks in which case the person borrowing has to come to the library and get the date extended. There is a limit on how much the user can extend the date of a particular book.
Best Answer
first impressions:
I'd say your include arrows are the wrong way round, it's a little odd that Validate membership isn't included in extend return date? and I'd also be tempted to split these into two or three separate diagrams (so we don't have crossing lines).
However, I'd also say that take 'correct uml' with a pinch of salt, if the diagram is useful to you, and to what you want to communicate, then it is doing its job already.