You will not find any information about how or in what chronological sequence these services are rendered (Figure 3.7): Figure 3.7 The elements of the use case diagram The relationships between actors and business use cases state that an actor can use a certain functionality of the business system. Lest expand our banking system use case diagram to show include relationships as well.Use case diagrams show business use cases, actors, and the relationships between them. The included use case is mandatory and not optional.The base use case is incomplete without the included use case.Few things to consider when using the > relationship. In some situations, this is done to simplify complex behaviors. The main reason for this is to reuse common actions across multiple use cases. Include relationship show that the behavior of the included use case is part of the including (base) use case. Include Relationship Between Two Use Cases Also, they have their own specific behavior to be modeled as a separate use case. These are not optional but depend on the account ledger entry. This might have extending use cases “Add Tax Ledger Entry” and “Add Payment Ledger Entry”. This mostly happens when your modeling complex behaviors.įor example, in an accounting system, one use case might be “Add Account Ledger Entry”. An extending use case can have non-optional behavior as well. Multiple actors can be associated with a single use case.Īlthough extending use case is optional most of the time it is not a must.An actor can be associated with multiple use cases.An actor must be associated with at least one use case.This one is straightforward and present in every use case diagram. Let’s take a look at these relationships in detail. There can be 5 relationship types in a use case diagram. If you want to draw them while learning you can use our tool to create use case diagrams. To get a deeper understanding of use cases, check out our use case diagram tutorial. This article will look into various use case diagram relationships in detail and explain them using examples. In fact many tend to confuse >, > and generalization. When it comes to drawing use case diagrams one area many struggles with is showing various relationships in use case diagrams.

Types of use case diagrams