Know the Use Case Diagram

Use-case diagram is a UML diagram that models used to describe the functional requirements expected of a system . Use-case diagram emphasizes on "who " did " what " within the software system to be built . Actual use-case diagram consists of two major parts , the first is the use case diagram ( use case dependencies including images ) and use case description .

Use-case diagram is a graphical depiction of some or all of the actors , use-case , and the interactions between these components are introducing a system to be built . Use-case diagrams to explain the benefits of a system when viewed in the eyes of people who are outside the system . This diagram shows the functionality of a system or class and how the system interacts with the outside world .

Use-case diagrams can be used during the analysis process to capture system requirements and to understand how the system is supposed to work . During the design phase , use-case diagrams serve to define the behavior ( behavior) when the system is implemented . In a model there may be one or several use-case diagram . Needs or requirements the system is what functionality should be provided by the system is then documented on the use-case models which describe the expected system functionality ( use-case ) , and that surrounding (actor ) , as well as the relationship between the actor and the use - case ( use-case diagram ) itself .

● Use case classes are used to model and express unit functions / services provided by the system ( or parts of systems : subsystems or class ) to the user .

● Use case can be covered with restrictions systems that are labeled name system .

● Use case is something that provides measurable results to the user or external system .

characteristics :
- Use cases are interaction or dialogue between the system and actors , including the exchange of messages and actions performed by the system .

- Use cases initiated by the actor and may involve the role of other actors . Use cases should provide a minimum value to the actor .

- Use cases can have an extension that defines specific actions in interactions or other use case may be inserted .

- Use case class has an object called a use case scenario . Scenarios expressed sequences and single action message .
 
 

Here is how to draw a use-case diagram :
Note :
Before making use-case diagram , you should start by making FDD first. This is just to help identify the processes in the system .
1 ) Start by registering actor associated with the Use - case , both the sender and receiver .
2 ) The components in a use - case diagram is a Use - Case Name , Description Use - case and participating actors and roles .
3 ) Find demonstrating dependency semantic relations between two Use - case . If the Use - case " A " change can result in Use -case " B " will change as well .
There are 2 kinds of dependencies that need to be considered which include and extend.

Dependency include :
A Use - case be able to include other functionality Use -cases as part of the process in itself . It is generally assumed that the Use - case that will be called whenever include Use -case - clicking executed normally include . A Use - case can be include by more than one other Use - case , so that duplication of functionality can be avoided by pulling out the common functionality .
Use - case examples ( include )

Description :
Patients must make an appointment before being given the care needed to treat the disease . Use-case " Make Appointment " go- include the functionality of the Use - case "Get Treatment " as part of the process when executed .

Dependency extend :
A Use - case can also extend the Use - case another with his own behavior . While the relationship between the Use - case generalization shows that the Use - case is that one of the other specialties .
Use - case examples ( extend ) :
 
 

Figure below shows an example schema Use Case Blog
 

Blogger login using your email and password , email , and password in the login Login extend the use case , as it requires the suitability of the data in the form of email and password. 

Aafter login will appear immediately blogger dashboard menu , there are view the blog and reading list , reading list for a reading list that can be seen by us when we have our blog followers . To view the blog is a function that we can use immediately to see our blog.
There we can see the profile in which the blogger dashboard profile menu sign out there to get out of there then edit profile account to edit our profile and account settings to reset our account
didasboard also include with the article that this article serves to fill our blog with articles, use case in the article are editing articles, delete articles, and post articles
can we call viewer or customer can see our blog article or in sub use case that bloggers post , then can provide comment to the article.

There are bloggers option to help us in the use of blogs, there are bloggers help, send feedback, uset edit settings, coonect to google+, about our new look