What is the difference between data normalization and denormalization?

Question

Accepted Answer

**Normalization** — reduce redundancy. **Denormalization** — optimize reads.

**Normalization:**
- Split data into related tables.
- Reduce redundancy.
- Improve data integrity.
- More complex queries (JOINs).

```
Normalized (3NF):
Orders(order_id, customer_id, product_id)
Customers(customer_id, name, email)
Products(product_id, name, price)
(No redundancy)
```

**Denormalization:**
- Combine data into fewer tables.
- Add redundancy.
- Optimize read performance.
- Simpler queries.

```
Denormalized:
Orders(order_id, customer_name, product_name, price)
(Redundant data, fast reads)
```

**Key differences:**
- **Normalization** — reduce redundancy.
- **Denormalization** — optimize reads.
- **Normalization** — write optimization.
- **Denormalization** — read optimization.

Systems Analyst: What is the difference between data normalization and denormalization?