I just create this diagram can anyone tell me if these 2 pictures are correct or wrong and which one should I use?, can anyone tell which is correct in these 2 pictures.
Both diagrams are ok, except:
the association between an actor and a use case should be straight lines and not directed arrows. These arrows are an obsolete practice.
the subject rectangle should be closed
actors not related to anything are useless and should be removed
The question of whether add and edit should be in the same use case or in distinct ones is up to you to decide:
grouping them has the benefit of simplifying the model. Manage students could be even more generic and is quite common.
keeping them separate may appear more granular but makes sense if there are different actors or if the business needs are very different.
You may read more to make up your mind, googling for CRUD Use case.
Related
I just create this diagram can anyone tell me if these 2 pictures are correct or wrong and which one should I use?, can anyone tell which is correct in these 2 pictures.
Both diagrams are ok, except:
the association between an actor and a use case should be straight lines and not directed arrows. These arrows are an obsolete practice.
the subject rectangle should be closed
actors not related to anything are useless and should be removed
The question of whether add and edit should be in the same use case or in distinct ones is up to you to decide:
grouping them has the benefit of simplifying the model. Manage students could be even more generic and is quite common.
keeping them separate may appear more granular but makes sense if there are different actors or if the business needs are very different.
You may read more to make up your mind, googling for CRUD Use case.
I want to create a very basic sequence diagram for the first iteration of my app. I have a database of exercises, and I have a use case for creating, another for editing, and another for deleting an exercise. They are all very simple, and use the same elements and actors, like User, DAO, and Database. What I want to do is to create a single SD, that begins with the user asking to create an exercise, followed by the user asking to edit that exercise, and then asking to delete it. My question is: is this considered correct in a sequence diagram? I don't want to create 3 SDs almost identical to one another, and this seems like a simple way to represent all the information, but I don't know if this is correct by UML standards. Thanks.
From a standards conformance point of view, there is nothing in the UML standard, that imposes a relationship between your use case models and sequence diagramme models. So, no matter how many use cases you want to reflect in a sequence diagramme, it would be neither "correct" nor "incorrect".
From a personal point of view : What you are asking about is a question of modeling style, not conformity. As long as the people who are reading your models understand them, you can do whatever you want. So, something like this would be perfectly fine :
The use case should depict this situation:
A shipman can ask questions via radio to either a VL, DM or WL. Depending on the question, they need to look it up in APIC (a software tool), but this is not always the case. They all are apic operators, but depending on their role, they have their speciality that they only can access in apic.
The question the shipman asks can be about lock executions, the nautical weather, etc... but it all comes down to the same question-answer format.
Is my use case correct?
Asking a question is usually not a use case. The goal of the shipman is probably not to ask a question, but to get some answers. So asking and anwering is one use case.
When analysing the use case, several possibilities will show up, such as looking up information in the APICS-system. I would just describe this within the use case (possibly with an Activity Diagram). What is the advantage of using an extend here? (I agree with the other answer, that the arrow is in the wrong direction. Additionally it should be an open arrow).
Each goal is an own use case, even when they have much in common. After describing the essential steps of the use cases, it may save some work to look at them and find those that have a big overlap in the essential steps and then create an abstract use case containing the commonalities. But this should only be done after describing the use cases.
Always remember, that the main goal of use case analysis is to find all functional requirements for the system, especially those that are not immediately obvious. If your use cases are just wrappers of functions you already know, not much insight is gained by them.
Three issues here:
The extends arrow is the wrong way around.
Generalizations of UCs is a bad idea in general.
Just as a side note: your actors miss their legs. This way it's a Female symbol (Venus' mirror).
Let's elaborate a bit on the 2nd. Why is it a bad idea? UCs represent a single added value for an actor a system under consideration will deliver. So each UC is unique (think of unique sales propositions). Generalization of USP is only valid in a franchise. So unless you model McDonalds here, it's likely a wrong approach. Look at the main UC "ask question". Do you consider that added value from a system? I wouldn't. When looking at the bubbles behind they more look like primary use cases. So, just remove that general "ask question" and connect the bubbles behind directly with Shipman.
As always when it comes to UC questions: Bittner/Spence about UC is the best read I can recommend.
[Original Title] : Does an actor need to point directly in use case diagram?
or can I do it like this?
in this Use Case Diagram, I want to say that actor can use any use case in the pointed group-of-use-case.
does this kind of thing allowed?
Edit #1
The reason why I ask this question, is because when I create this use case there's a lot of line intersecting each other that makes me confuse.
And there's a comment :
It would be better to split that into smaller diagrams
does it mean like this?
Edit #2
after reading comment :
A UseCase specifies a set of actions performed by its subjects, which yields an observable result that is of value for one or more Actors or other stakeholders of each subject.
so I decided to change to this :
is this how a use case diagram should be?
Edit #3
CONCLUSION
An actor should point directly to use case
Read more the detail about how a Use Case Diagram should be in comment on this question
To be UML compliant you can not do that. But I guess one can understand what you are trying to communicate.
As a side note: Login is not a business use case. It is a constraint. Also with CRUD use cases I would not separate them but have a Maintain <object> instead (which itself is some borderline use case since maintaining something is not directly business relevant). You can constrain maintenance operations to certain actors separately.
Edit Regarding Login (one of my favorites): Use cases are most commonly used to describe business context (exactly as you are doing). So when looking from a business perspective, a Login is not a use case, but a simple constraint (you can do the business relevant things only when you are logged in).
Now for the Manage/Maintain use cases. They are on a similar level. Usually the "managing" itself is not directly business related. In many cases the focus on the real business was lost. So instead the reason why you manage something is the real use case (e.g. Correct User Data, Collect User Data). This is quite challenging and I confess that sometimes I also fall back to Manage. Most people don't bother but doing a good job requires to think over basics and not adopt bad habits.
This question already has an answer here:
Have I to use the same actors for those extending or included use cases? [closed]
(1 answer)
Closed 6 years ago.
I am currently refreshing/altering my knowledge in software development because I will work in this area soon. We have learned a lot about UML diagrams and coding at University, but I have never brought it all together in a real Project. Therefore, I started to create a test web-app in Grails, and I wanted to begin with a requirements analysis and use cases too keep it close to reality.
My web-app should allow users to share recipes, find recipes and review recipes by other users. Every recipe has many ingredients, which are not just strings but rather entities so that calories, fat, protein and carbs can be used to automatically calculate nutrition facts of a certain recipe.
An ingredient can be added to the database by either a consumer or nutrition expert. If it is created by a consumer, it is only a "prospective" ingredient, meaning that it has to be verified by an administrator to become a "proper" ingredient -- otherwise it is marked, e.g. red text color.
This is my current use case diagram:
http://ubuntuone.com/0zDw9kEbj1BwtXjnCtxdwC
My question here is:
Can extending or included use cases be accessed independently? If I do it as in the screenshot, can AddProspectiveIngredient be used without going through the CreateRecipe use case? Same question for included use cases.
EDIT: I don't think this is a duplicate of this question. In the linked question (1), I ask if I have to use the same actor for extending and included use cases as in the extended or including use case. In this answer (2), however, I merely ask about reuse between use cases.
In (1) it is all about the actor, and I am very satsified with this answer, as I now understand that the primary actor of an extending use case will inevitably be a subclass of the primary actor of the extended use case.
(2) addresses reusability of extending and included use cases, but is not necessarily connected to actors. It is about reusing them in other use cases. So if I have two use case CreateRecipe (a) and AddIngredientToDatabase (b), where (b) extends (a), can I also extend a third use case with (b)? Here I also received my answer, that they can and should be reused.
Maybe the questions seem similar because I created them on the same day with the same example and the answers both mention actors, which make them seem as duplicates. As they are both answered and I am satisfied with both answers, why close the questions as "too broad" or "duplicates"? If it was answered succesfully with different answers, how can it be too broad or a duplicate?
I am also happy to rephrase them slightly to keep them open, if I am told what the core issues. More answers and comments on the topics are still interesting to me.
Can extending or included use cases be accessed independently?
They rather should be. It is a good and correct style. Use case is some activity conducted between one or more actors and system. You should try not to show here some inner operations, that are not connected to users. Nothing invisible to users can be shown here. USER cases, remember?
So, no inner structure here.
You can collect some cases in groups - subsystems. But it is not inner structure, they are not IT systems, they are simply common themes of activities, obvious for users. Such subsystems should get later at least common UI style.
As for logic that could be used by users, it can be shown on other diagrams. Many diagrams can exist on this level - State machines, Activities, Timing. But don't try to show processes on the Use case diagram, too.
So, I don't know how well have you interviewed the client, but you use case diagram looks almost correct. Only the AddProspectiveIngredient Use Case should get its user or more.