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Hello I'm studying sequence diagram.
For example there are 2 actors,
an actor is a trader who has an online shop.
Another actor is a customer who buys the trader's products.
How do I represent the situation when the trader is storing the products into a database or when the customer is buying a product?
The possible use cases are insertProduct and buyProduct.
The database is part of the system, so no other actor communicates with the system.
I've not understood how to represent this situation when the communication among actors is not in "real-time".
Thanks in advance.
You will need to split things as #JimL suggests. Your use case is best be shown with an activity diagram where you have single actions representing the steps like search/pay/etc.
When you design your domain you will then find technical classes like Store etc. where your actor can send messages like buy(item) etc.
The whole story is somewhat more lengthy and will definitely be off-topic for SO.
You seem to be mixing up two levels of interaction. One happens at the business level, in the "meat world", where people interact. The trader and customer might only interact directly when the customer has a question. The other happens at the system level, between an actor and the system. The latter would show how the trader stores a product OR how a customer buys a product, not both.
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I made this use case diagram:
My project is a village profile website. It is made for collecting the questions from the researcher who wants answers directly from the locals, for any reasons: covid, communication etc.
As I am not experienced with use-cases,I want to make sure that I am going in the right way. Is this diagram correct?
A use-case diagram is about the big picture and the goals (use-case bubble) that a system (the rectangle) helps its actors to achieve.
According to your diagram, there would be 5 independent systems, each with some use-cases that address different needs. Is this really what you wanted to model?
When zooming into the different systems, it appears that these are not independent systems but function groups (i.e. groups of features that offer some functionality). It appears moreover that the use-cases do not correspond to user-goals, but to detailed functions related to the function group. So you seem to do some kind of functional decomposition.
Functional decomposition is fine. But not with use-cases! It always leads to very detailed diagrams that loose the big picture and end to be unrelated to the user’s interest.
Use-cases are not either meant for user-interface design (in case you wanted each rectangle correspond to some windows/pages), or for decomposing the internal structure of the system (in case you wanted each component to correspond to some microservice or whatever). Use-case should focus only on user goals that add value to the user (typically not a login, which is only a constraint for what the user really want to do).
Good news: there remains good potential to significantly simplify this diagram ;-)
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I'm unsure on how this relationship would work in a use case. I was hoping somebody would shed some light on this for me by explaining the relationship and the behaviour accessible by each?
This relationship is not allowed in UML 2.0.
UML 2 does not permit associations between Actors. (1)(2) The use of generalization/specialization relationship between actors is useful in modeling overlapping behaviours between actors and does not violate this constraint since a generalization relation is not a type of association.(3)
(Wikipedia)
Although Applicant is a valid concept to the system, (s)he is not a system user; therefore, it should not be an actor in the use case diagram. Even for regular use case descriptions this relationship does not matter. What matters is the user and system interactions. However, you are free to explain this relationship in a user story.
Although this is legal UML it does not have a well defined semantic. It says: Applicant is associated with Artist Manager but does not tell what kind of relation that is.
Just think by yourself: what does it tell? If you can't give a meaningful answer then it's probably nonsense.
Judging from the UC I guess that Applicant is a secondary actor. You should relate it to the UC like Artist Manager. In the past I used an undirected association for the secondary actor. Alternatively you may stereotype it with <<use>> or the like. Just be consistent with the notation.
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I just drew an activity diagram, and I have 14 actors in my case. (I am making an activity diagram of online shopping site.)
Anyway... I am facing a problem with it, I am curious whether I must draw all actors in my diagram.
I have few system actors, so I am confusing how I place those actors between normal actors and system actors.
There are seller, non-seller who only buy products, and a manager who checks product posts. And finally I have to draw shipping system, certifying credit system, and more.
Thank you.
Well, I would say your use case is cut the wrong way. If it involves 14 actors then it looks like a pot of spaghetti and you did not sort out well. Look at the use case and try to find out what is wrong. There should not be more than 3 actors involved.
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i am sorry for asking such a straight forward and simple question but there is a lot of confusion regarding the use of partition in activity diagrams like :
is it really necessary to create partitions?
since each organisation has a number of working units/sub-units,and eventually they will have roles to play,would we
need to create partitions in literally every activity diagram we draw
for any process flow?
e.g- suppose we have draw an activity diagram for online shopping .customers browse and search for items and later buy it .now there are very fewer roles here so we can clearly draw the diagram without partitions but still we can create them ,in both case they will represent the system so does it really make sense to create them.
The answer to both questions is No.
Partitioning is an optional feature for an activity diagram.
UML is most of all a means of communication. When partitioning adds useful information to the ddiagram, then you should include it. When it doesn't add anything to the message presented by the diagram, then you don't add it.
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Are user stories (typically used in agile development or test driven development) the same thing as events in Edward Yourdon's structured analysis methodology?
Events and user stories are related but not identical. A Yourdon event is any stimulus to the system that requires the system to respond, so, for example, a tick from an external clock could be an event. That might require a response, eg, by incrementing a counter, but it wouldn't necessarily lead to a result with direct business value to the customer, so wouldn't be a valid user story or use case.
A user story is a pattern for briefly describing a business, technical or other type of need.
For example:
As a risk analyst I would like to add references to the application page so that we can store the references with the application, where the verifications team can then use them to help improve our risk rate in our underwriting.
Then in your user story you would decompose the story describing what tasks will be needed to complete the "would like" with a "done" check point being the "so that".
Mike Cohn has a good article on User Stories and the advantage of them http://www.mountaingoatsoftware.com/articles/27-advantages-of-user-stories-for-requirements
As far as Edward Yourdon's structured analysis methodology, I have to admit I'm not extremely familiar with it so I cant answer that part of your question.
That´s right, user stories and use cases from UML are rewrites of Yourdon´s events. They are just a reinvention of the wheel.