Create a sequential diagram for each use case in the online shopping system [closed]

Question

According to this use case diagram, I have to draw a sequence diagram for each use case except login by making an assumption. For example, when I come to the checkout sequence diagram, I can assume that the procedure is done through view items, but in the view items sequence diagram, I must clearly draw the procedure sequence. I googled and learned about sequencial diagrams, but I didn't find anything like this. I'm trying to sketch some use cases, but for example, when it comes to completing checkout, there are many actors, and I'm not sure how to do it when there are more actors.

I created a sequence diagram for login, but I don't know if I have to take authentication as an actor or not. This is my sketch.

That is my login sketch, which I made.

I need just a guide on how to draw a complete checkout and make a purchase sequence diagram separately. like how we draw when we have several actors. Please give me some advice and instructions on how to do it.

Thanks in advance.

Answer 1

Well, a sequence diagram can have multiple actors, but according to this question, I think login is correct. Also, when you create the sequence diagram separately for complete checkout, there are no actors, and you can make whatever assumptions you want that are mentioned in the question above. I think this will help you sort out your problem a little bit.

Answer 2

You have multiple issues, but the most important issue seems to be about how to deal with multiple actors in a sequence diagram. If you want to know how to create sequence diagrams for use cases that have an include relationship, please open a new question focusing on that issue.

One may include multiple actors in a sequence diagram. Usually, the primary actor is shown at the left-hand side of the sequence diagram and the secondary actors are shown at the right-hand side.

Strictly speaking, your sequence diagram will not contain actors, but it will contain so-called lifelines, representing elements of type actor. To refer to actor Customer, you could label the stickman :Customer.