What is ACID in SQL? Real-World Examples Explained

In the database world, ensuring that data is processed correctly and reliably is critical. ACID (Atomicity, Consistency, Isolation, Durability) principles are designed to ensure this reliability for data types and database transactions. In this article, we will explain ACID principles with real-world examples.

1. What is ACID?

ACID refers to four fundamental principles that ensure data integrity in database systems:

• Atomicity: A transaction must be fully completed or not executed at all.
• Consistency: A transaction must transition the database from one valid state to another.
• Isolation: Concurrent transactions must not interfere with each other.
• Durability: Once a transaction is committed, it must be permanently stored.

2. Real-World Examples of ACID

Atomicity — Bank Transfer

In a bank, when person A transfers money to person B, the process consists of two steps:

1. Deduct money from A’s account.
2. Deposit money into B’s account.

If either of these steps fails, the entire transaction should be rolled back. If the money is deducted from A but not deposited into B’s account, the transaction must be fully reversed.

Consistency — Inventory Management