Is this use case diagram over complicated? I'm trying to implement a use case for the first time, and I'm trying to get it within the ball park.
Jordan, your use case is missing out the system name at the top.
And there is no over-complicated Use Case Diagram, as long as it fits the requirements of the client.
P.S: By the way, the following Use Case Diagram is one of my assignment in school (so it's not for a system to be built, but similar anyway). It's way complex than what you have there, but it's not over-complicated because the system needs all these use-cases. Imagine drawing the use case of Twitter or Facebook.
Merlion University Student Association System Use Case Diagram
Doesn't look overly complicated, but you're missing the part that goes on the right, which is the actions in the box use/affect. For example, Add Account may communicate with a database, in which case you'd put a box on the right (outside of the center box) called Database and have Add Account point to it.
Related
With this Use Case diagram, I'm unsure if I'm currently doing it correctly or not. Checked online and each site is giving me a different answer. I just need a direction or someone to correct me.
This is interesting as I am currently going through the exact same discussion with a client...
I would say "no" simply because I am unsure of what this actually represents.
A use case must bring a benefit to a user, and I really don't this in this diagram. What does Actor0 actually trying to accomplish? I do not get this from the diagram.
Did you write down statements before trying to do this? I find that going to a whiteboard and writing down what your actor's goal and how you see this happening so that the actor achieves the goal is a good start to better understanding the use case and differentiate the system being built from external systems. One way to do this is through a set of user stories (or use case slices).
And answering Thomas Kilian's excellent questions will also help you in this task!
Also, you are doing something that I see too often from people starting with use cases (and sometimes with UML experience): use case decomposition as a set of actions - basically trying to model a set of activities by breaking it down. Doing that is typically the second step in your analysis (e.g., by using activity and sequence diagrams).
No. Only "Register" (what?) and "Add/View Details" (which?) can be regarded as use cases since they add value. Neither "Login" nor "Main Menu" are use cases. The first is a constraint and the second an implementation detail.
Case(Detailed): User select some files in android applicaiton and send SOAP request to WebService to set the selected files as Favorite.
Case(With few words): User want to set some files as favorites
Sequence Diagram is:
User-->FileBrowser-->WebService-->DbManager-->Database
So, is the below diagram correct or i am missing something?
Your diagram looks fine. However, I noticed from your other question that you are now mixing business and technical aspects. If you want to do a use case synthesis for the business (which is the most common application of that) you must not start mixing technical aspects. Having said this, Login is not a business use case. A use case describes in short terms the added value which an actor receives when applying it. On a business level, a login is just a constraint since it does not add any value.
As an advice:
Start with use cases on a pure business perspective.
Think what actually is added value.
Which are the stakeholders?
What are their requirements?
Which requirements can be synthesized to use cases?
Only after that start a technical design. In that you may use use cases on a technical level where you may describe a Login use case as part of an authentication sub-system.
Should you not include some kind of system, whereby user and server is outside of it? My teachers always commented on involving the system.
List all the users outside the system. The use case serves as an answer to:"What will the system do?". Is the database used by external users/systems? In that case it's better to represent it as a seperate actor.
Perhaps an idea to write a full use case before making a use casediagram.
Two things are not according to UML:
The include dependency should have an open arrowhead pointing to 'selct file'.
The word include must be surrounded by «guillemets»
Recommendations:
Use a consistent naming convention for the use cases. It is common to use imperative style, with at least one verb and one noun e.g. "Select file" and "Choose favorite files".
Draw a system boundary (rectangle) around the use cases, leaving the actors outside of the boundary. Enter a descriptive name inside the boundary, e.g. "Android app".
I would like to show use case diagram me.What is correct use case diagram me about system hotel?
http://i.stack.imgur.com/KPsZU.png
Note :
- outside of system boundary is comment, Not use case
sorry don't have reputation 10. Don't show image this.
After a short review I would say that your use cases don't seem to be cut the right way. You are using <<include>> and <<extend>> in order to perform a functional analysis. This is not what use cases are all about. Each use case must show a piece of added value to its actor. I/E are a means of showing optionality for single UCs (means they can be added later in time or build a system with different level of value to the user). Showing a path of execution is something that goes completely into activity diagrams inside each use case.
As a take home message: If your UC diagrams start resembling a spider's web your design is likely broken.
suppose you have to do a Use Case Diagram for this simple problem (that is part of a much bigger exercise i am doing):
a registered user (of a web application) can search for tourist attractions in two ways: by category (for example: museums, parks, theaters, archaeological sites) or by location (city, county).
How should i model this UCD?
The most simple way would be: the actor (registered user), two use cases (search tourist attraction by category and search by location), the secondary actor (the server of the web application, which would process the query and send back the results).
My concern is that in this way the four categories and the two type of locations would not be present in the use case.
I was thinking of using the "extend" relationship. For example, i would add a use case named "Search parks" that extends the use case "Search by category". The extension point would be the event that the user chooses to search for parks.
Or i could use an inheritance relationship between the "Search by category" and "Search parks"...mmmm...i am a little confused...
How would you model this little problem using USD??
Thank you,
Luca
First of all you have to realize, that Use Case Diagrams aren't substitute for actual (written) Use Cases. Use Case descriptions contain many important details, which are omitted in Use Case diagrams. Use Case diagrams are good for depicting hierarchies of actors, associated use cases and relationships between use cases, but nothing more.
Another important thing is to realize what an use case actually is. Good way to think about them is to find a goal of an actor, which he/she wants to achieve with help from the system. Achieving this goal should give the actor some business value. My point is, that from what you described, registered user might want to search for a sightseeing and/or buy entry tickets. So this is his goal and this should be a an use case, don't confuse use cases with functionality/features like different ways of searching etc.
In your first suggestion you have two use cases, which differ only in data (e.g. it might be just different choice from a combo box in a form). Such differences, if they don't influence the way the system and actors interact, are described separately from the use cases in a data glossary, which you reference in your use case. This way you avoid many unnecessary details in use case descriptions. If on the other hand, the steps in the description change (e.g. when registečred user chooses location system gives him/her an option to select another registered user as a friend and pre-selects favourite locations of both or something like that...), you can capture this by using alternatives/extensions.
You mention the system you are developing as the secondary actor. Don't forget, the system under development is an implicit actor and is not shown diagrams as a separate actor. Use boundary box (rectangle encompassing use cases excluding actors) to depict scope of your system.
Finally to your concern. These are all just details about the data, which are not part of an use case. You can capture those details in text (by namicng all categories etc.) using the data glossary as mentioned above. If you think the structure and relations between data is important and needs to be captured using diagrams, you can use class diagrams to create data/domain models.
Last note about use case relationships - don't use them if you don't have to. They are often hard to understand and vaguely defined. Never ever use them to decompose the functionality, that is up to design, not analysis with use cases.
I hate depicting Search in a use case. There are simply too many variables. It's like trying to write a use case for using a browser.
Search is a good candidate for early prototyping supplemented with business rules.
On a Use Case diagram can you show things that an actor cannot do, for example because they won't have permissions to do it?
Or is it just implied due to the fact that they won't have a line joining them to the particular use case?
If the Use Case you are diagramming is the case where an actor attempts to do something that is not permitted and is then denied, then yes, I would show it.
Otherwise, I would stick to only including things that are actually part of the use case.
No. An Actor would be connected to everything that he can do. If the Actor can't do it, then it's not shown.
This is what alternate paths are for. The basic path (a.k.a. happy path) will show what happens when the correct Actor initiates the Use Case. In the alternate paths you can show what happens if the wrong Actor attempts to initiate it.
You might model Role actors that can do the task. You could then have another use case that has the original actor attempting to acquire the given Role.
IMHO this question and most of the answers give a wrong impression about the way use cases should be used.
Use case was intended as a requirements technique that uses natural language. It is most and quite effective that way.
It can be a thoroughly destructive technique when it is combined with too much UML/modeling. Structured modeling of use case texts for example by modeling main and alternative flows using UML Activity Diagrams is a tried and tested way for example to create Use Cases of Mass Destruction.
A use case diagram can be useful but we should remember the purpose of use case as a technique which is first and foremost to identify the user goals a system should support. Subsequently we can capture more details using natural language in use case texts using main flow, alternative flows etc.
Using diagramming tools we can visualize some simple information:
- For each user goal we can create model element type Use Case.
- Show system boundary using a box for the system with use case elements in it.
- Create a relationship between actor and use case to show the actor has a particular goal against the system.
Keeping an up-to-date list of actors mapped to goals is however of secondary importance. Doing a stakeholder analysis, drawing up lists of actors is a means to identify the users goals. After user goals have been identified it is strictly speaking not longer necessary to keep the lists of actors around.
If we are asking questions about how to put user permissions in a use case model we are most likely trying to capture too much information. We should abstract model elements away so that the model does not try to answer/capture these type of detailed design questions.