What is the difference between UML and ERD?

Question

Accepted Answer

**UML** — unified modeling. **ERD** — entity-relationship.

**UML (Unified Modeling Language):**
- Comprehensive modeling language.
- Multiple diagram types.
- For system design.
- Behavioral and structural.

```
UML Diagram Types:
- Use Case Diagram
- Class Diagram
- Sequence Diagram
- Activity Diagram
- Component Diagram
- Deployment Diagram
```

**ERD (Entity-Relationship Diagram):**
- Specific diagram type.
- Data modeling only.
- For database design.
- Shows entities and relationships.

```
ERD Example:
Entities: Customer, Order, Product
Relationships:
- Customer --< Order
- Order --< OrderItem
- OrderItem --> Product
```

**Key differences:**
- **UML** — comprehensive.
- **ERD** — specific.
- **UML** — system design.
- **ERD** — database design.

Systems Analyst: What is the difference between UML and ERD?