By Matt Errey, creator of the popular ESL board game WORD UPintermediate-advanced“I bought this ebook because most of my students have a problem with phrasal verbs.I use the quizzes to test them and find out which phrasal verbs most of them don’t know.Note how for some use cases there is more than one actor involved.
Use case diagrams depict: In the example depicted in Figure 1 students are enrolling in courses with the potential help of registrars.
Professors input the marks students earn on assignments and registrars authorize the distribution of transcripts (report cards) to students.
The preceding paragraph describes my general use case modeling style, an "actors first" approach.
Others like to start by identifying one actor and the use cases that they're involved with first and then evolve the model from there. The important point is that different people take different approaches so you need to be flexible when you're following AM's practice of Model With Others.
Perhaps a registrar may notice a student needs help and offers assistance, whereas other times, the student may request help from the registrar, important information that would be documented in the description of the use case. I generally don't include arrowheads on the association lines because my experience is that people confuse them for indications of information flow, not initial invocation.