Exercise 1.5: Creating the Account Operations use case diagram

In this exercise, you create the Account Operations use case diagram by modeling the relationships between the actors of the system and the use cases.

The account operations use case model describes the interactions between the actors and the use cases of the PiggyBank online banking system. In the previous exercises, you identified the use cases and actors. You can now describe the interactions of the users and the system by modeling the relationships between the actors and the use cases.

Modeling the relationships of the Customer actor

You can complete the use case diagram by modeling the relationships between the actors and the use cases. Customer is a primary actor in this use case diagram.

To model the Customer relationships:
  1. In the Model Explorer view, expand Account Operations and double-click Account Operations Use Cases.
  2. In the Palette, click Association.
  3. In the diagram editor, click the Customer actor and drag the cursor to the Display balance use case element.
  4. In the Palette, click Association.
  5. In the diagram editor, click the Customer actor and drag the cursor to the Transfer money use case element.

You have now modeled the relationships of the Customer actor in the use case diagram. The Customer actor can display the balance of an account, and can transfer money from one account into another.

Modeling the relationships of the Teller actor

You can complete the use case diagram by modeling the relationships between the actors and the use cases. Teller is a primary actor in this use case diagram.

To model the Teller relationships:
  1. In the Model Explorer view, expand Account Operations and double-click Account Operations Use Cases.
  2. In the Palette, click Association.
  3. In the diagram editor, click the Teller actor and drag the cursor to the Display Balance use case element.
  4. In the Palette, click Association.
  5. In the diagram editor, click the Teller actor and drag the cursor to the Transfer Money use case element.
  6. In the Palette, click Association.
  7. In the diagram editor, click the Teller actor and drag the cursor to the Cash Check use case element.

You have now modeled the relationships of the Teller in the use case diagram. The Teller actor can display the balance of an account, can transfer money from one account into another, and can cash a check.

Modeling the relationships of the CityBank actor

You can complete the use case diagram by modeling the relationships between the actors and the use cases. CityBank is a secondary actor in this use case diagram.

To model the CityBank relationships:
  1. In the Model Explorer view, expand Account Operations and double-click Account Operations Use Cases.
  2. In the Palette, click Association.
  3. In the diagram editor, click the CityBank actor and drag the cursor to the Cash Check use case element.

You have now modeled the relationships of the CityBank actor in the use case diagram. The CityBank actor is responsible for validating checks that PiggyBank customers cash. The CityBank actor is the only nonhuman actor in the diagram. Your diagram should look similar to the following figure:

The complete PiggyBank use case diagram.

The use case diagram in the figure shows the cardinalities of the relationships. Cardinalities can make simple diagrams appear cluttered. To remove the cardinalities in the diagram, right-click in the diagram editor; then click Filters > Hide Connector Labels.

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