Each use case describes _____ function(s) in which users interact with the system.

Use situation diagram is a behavioral UML diagram type and commonly provided to analyze various units. They permit you to visualize the various kinds of functions in a mechanism and also how those functions connect via the mechanism. This usage situation diagram tutorial will cover the following topics and also assist you produce usage situations much better.

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How to develop usage case diagrams ( with instance )

Importance of Use Case Diagrams

As stated prior to usage situation diagrams are supplied to gather a intake requirement of a mechanism. Depfinishing on your necessity you deserve to use that information in different means. Below are few ways to usage them.

To recognize features and also exactly how duties communicate with them – The main function of use instance diagrams.For a high-level see of the system – Especially useful when presenting to managers or stakeholders. You have the right to highlight the duties that interact through the mechanism and the usability offered by the device without going deep into inner woremperors of the system.To identify interior and exterior factors – This could sound easy yet in large facility tasks a device deserve to be identified as an external function in one more use case.

Use Case Diagram objects

Use case diagrams consist of 4 objects.

ActorUse caseSystemPackage

The objects are better defined below.


Actor in a use instance diagram is any entity that performs a role in one given system. This might be a perchild, organization or an outside device and typically attracted like skeleton shown listed below.


Use Case

A use situation represents a function or an action within the system. It’s drawn as an oval and also called via the function.



The system is used to define the scope of the usage case and attracted as a rectangle. This an optional aspect but useful as soon as you’re visualizing big units. For example, you deserve to create all the usage instances and then usage the mechanism object to define the scope spanned by your project. Or you can even usage it to show the different areas covered in different releases.



The package is one more optional aspect that is exceptionally valuable in complicated diagrams. Similar to class diagrams, packages are offered to group together usage cases. They are attracted prefer the photo shown listed below.


Use Case Diagram Guidelines

Although use case diagrams have the right to be supplied for miscellaneous functions tbelow are some common guidelines you need to follow when illustration usage situations.

These include naming criteria, directions of arrows, the placing of use cases, intake of system boxes and additionally appropriate consumption of relationships.

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We’ve extended these guidelines in information in a sepaprice blog write-up. So go ahead and inspect out use case diagram guidelines.

Relationships in Use Case Diagrams

Tright here are 5 types of relationships in a usage instance diagram. They are

Association in between an actor and also a use caseGeneralization of an actorExtend relationship in between two use casesInclude connection between 2 use casesGeneralization of a usage case

We have extended all these relationships in a sepaprice blog article that has examples with imperiods. We will not go right into information in this write-up however you have the right to check out relationships in usage situation diagrams.

How to Create a Use Case Diagram

Up to currently, you’ve learned around objects, relationships and also guidelines that are critical as soon as illustration usage case diagrams. I’ll explain the miscellaneous procedures making use of a banking device as an instance.

Identifying Actors

Actors are outside entities that communicate with your system. It deserve to be a perchild, an additional mechanism or an organization. In a banking system, the the majority of apparent actor is the customer. Other actors deserve to be bank employee or cashier relying on the duty you’re trying to display in the usage situation.

An instance of an outside organization have the right to be the taxes authority or the main bank. The loan processor is a good example of an external system connected as an actor.

Identifying Use Cases

Now it’s time to determine the use instances. A excellent way to do this is to recognize what the actors need from the system. In a banking system, a customer will certainly need to open up accounts, deposit and withdraw funds, research check publications and comparable features. So all of these have the right to be thought about as usage cases.

Top level usage situations must always administer a complete function compelled by an actor. You have the right to extend or include use instances depending upon the complexity of the mechanism.

Once you determine the actors and also the top level use instance you have actually an easy concept of the device. Now you can fine tune it and include additional layers of detail to it.

Look for Usual Functionality to usage Include

Look for prevalent use that deserve to be reoffered across the system. If you discover 2 or even more usage cases that share common functionality you can extract the prevalent attributes and add it to a separate use instance. Then you can attach it through the incorporate partnership to show that it’s constantly called once the original use situation is executed. ( check out the diagram for an example ).

Is it Possible to Generalize Actors and Use Cases

There might be instances where actors are connected with equivalent use situations while triggering a couple of usage cases distinct just to them. In such instances, you have the right to generalize the actor to display the inheritance of features. You have the right to carry out a comparable thing for use case also.

One of the best examples of this is “Make Payment” usage case in a payment device. You have the right to even more generalize it to “Pay by Credit Card”, “Pay by Cash”, “Pay by Check” and so on All of them have the attributes and the use of payment with one-of-a-kind scenarios distinct to them.

Optional Functions or More Functions

Tbelow are some features that are triggered optionally. In such situations, you can usage the extfinish partnership and affix an expansion dominance to it. In the below banking mechanism instance “Calculate Bonus” is optional and only triggers when a particular condition is matched.

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Extend doesn’t constantly intend it’s optional. Sometimes the use instance connected by extending have the right to supplement the base use instance. The point to remember is that the base use case need to have the ability to perdevelop a function on its very own even if the extfinishing use situation is not called.