What is a use case vs business rule?

Question

Accepted Answer

**Use case** — system functionality. **Business rule** — constraint on behavior.

**Use case:**
- Describes functionality.
- Actor interactions.
- Steps to complete.
- System behavior.

**Business rule:**
- Defines constraints.
- Policies and conditions.
- Governs decisions.
- Can be automated.

**Example:**
```
Use Case: Place Order
1. User adds items
2. User enters payment
3. System processes order

Business Rules:
- Orders over $50 get free shipping
- Credit card must be valid
- Maximum 10 items per order
```

**Key differences:**
- **Use case** — what the system does.
- **Business rule** — how it should behave.

Business Analyst: What is a use case vs business rule?