UML - Use Case Diagram

UML stands for unified modeling language. It is used to create a blueprint for a project.

A use case diagram is a list of steps needed to reach a goal. Its defines what is required and how those requirements are met.

You will narrow down what you have to have.

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Before you create a use case diagram you need to create a description of the use case diagram. For example the above would look something like this:





Use Case Specifications Example 2: ATM Machine Use Case Description: Allows any bank customer to obtain cash from their bank account. This use case begins when an ATM customer chooses a type of account from which the cash is to be withdrawn (e.g. checking) from a list of possible accounts, and to choose a dollar amount from a list of possible amounts. The system sends the transaction to the financial system for verification. If the financial system approves the transaction, the machine dispenses the appropriate amount of cash and issues a receipt. The dispensing of cash is also recorded in the ATMs log Use Case Name: Withdraw Cash Actors: . Any Bank Customer (Has an existing account) . Banking System (Any banks ATM and its infrastructure) Triggers: . The user wants to withdraw money from one of his/her account. Preconditions: . The ATM is operational » The bank customer has a card to insert into the ATM Post conditions: » The bank customer has received their cash (and optionally a receipt) » The bank has debitedthe customers bank account and recorded details ofthe transaction Normal Flow: 1. The customer enters the bankcard into the ATM 2. The ATM verifies that the card is a valid bankcard 3. The ATM requests a PIN code 4. The customer enters the PIN code 5. The ATM validates the bankcard against the PIN code. 6. The ATM presents service options including Withdraw 7. The customer chooses Withdraw 8. The ATM verifies sufficient funds in the customers bank account. 9. The ATM presents options for amounts. 10. The customer enters an amount. 11. The ATM verifies that the customer is below withdrawing limits.

Use case descriptions includes who the actors are, what the triggers are, and other elements.

Beta versions of a project have Shall requirements, should requirements can be done but can be done later.

A use case diagram uses stereotypes to represent an element of your system.



https://whatis.techtarget.com/definition/use-case-diagram

https://www.youtube.com/watch?v=OkC7HKtiZC0

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