Question

A bank account has an owner and a balance. There are two different types of bank accounts: (1) checking accounts and (2) savings accounts. Checking accounts have an insufficientFundsFee whereas savings accounts have an annualInterestRate.

Design a UML diagram that captures this scenario correctly and concisely.

Answer 1

In summary, a UML diagram for bank accounts would consist of a general BankAccount class with attributes for owner and balance. Subclasses CheckingAccount and SavingsAccount would inherit from this, with CheckingAccount adding an insufficientFundsFee attribute and SavingsAccount an annualInterestRate attribute. This design typifies the specialized features of both account types in a banking context.

Step-by-step explanation:

A bank account is characterized by having an owner and a balance, with two principal account types: checking and savings. Notably, these accounts have different features tailored to their usage purposes. For a clear and concise UML diagram representation, one must highlight these differences accurately.

UML Diagram for Bank Accounts

• BankAccount: This is a general class representing a bank account with two key attributes: owner (String) and balance (double).
• CheckingAccount: This subclass inherits from BankAccount and adds an additional attribute called insufficientFundsFee (double) to represent fees charged on overdrafts.
• SavingsAccount: Similarly, this subclass derives from BankAccount, including an annualInterestRate (double) attribute signaling the interest earned annually on the savings.

These two specialized types of accounts, checking and savings, cater to distinct financial needs, as articulated by banks. While a checking account often has easier access mechanisms such as checks and debit cards but offers little to no interest, the savings account accrues interest over time, although it may require a physical visit to the bank or ATM, or an electronic transaction for fund access. Over the years, however, the boundaries between these account types have begun to merge, with some checking accounts offering interest rates and some savings accounts providing limited check-writing capabilities.

Designing a UML diagram entails not only depicting these classes and attributes but also visualizing the relationship between these entities, which is typically a generalization or inheritance depicted with a line and an unfilled arrowhead from child classes to the parent class.