ACID Properties in SQL

?ACID is an acronym that stands for Atomicity, Consistency, Isolation, and Durability. These four properties are essential in ensuring that data stored in a relational database management system (RDBMS) like SQL is reliable, consistent, and secure. Here's a brief explanation of each of the ACID properties:

1. Atomicity: This property ensures that a transaction in SQL is treated as a single, indivisible unit of work. Either all the operations in the transaction are completed successfully or none of them are. If an error occurs during the transaction, all the operations are rolled back to their original state, ensuring that the database is left in a consistent state.

1. Consistency: This property ensures that any transaction in SQL leaves the database in a consistent state. In other words, the data is always valid and conforms to the database schema. If any operation in a transaction violates the consistency rules, the entire transaction is rolled back, ensuring that the database remains consistent.

1. Isolation: This property ensures that transactions in SQL are isolated from each other. This means that a transaction should not be affected by the actions of other concurrent transactions running simultaneously. Each transaction should execute as if it were the only transaction running in the system. This ensures that the data is accurate and consistent.

1. Durability: This property ensures that any changes made to the database in SQL are permanent, even in the event of a system failure or power outage. Once a transaction is committed, its changes are stored in non-volatile memory, ensuring that they are available even after the system restarts.

ACID properties of SQL ensure that transactions in a relational database are executed in a consistent, reliable, and secure manner. This helps to maintain the integrity of the data and ensures that the database remains stable even in the event of failures or unexpected errors.

Real-Life Examples of ACID Properties:

ACID properties of SQL help to ensure that the transactions are executed in a reliable, consistent, and secure manner, even in the event of unexpected errors or failures.

1. Banking transactions: When a customer withdraws money from an ATM, the transaction is treated as a single unit of work (atomicity). If the transaction is successful, the customer's account balance is updated to reflect the withdrawal, and the database remains in a consistent state (consistency). The transaction is isolated from other concurrent transactions, so the customer's account balance cannot be affected by other customers' transactions (isolation). Finally, the transaction's updates to the customer's account balance are permanent, even if the ATM or the system crashes (durability).

1. Online shopping: When a customer places an order on an e-commerce website, the transaction is treated as a single unit of work (atomicity). If the transaction is successful, the customer's order is saved to the database, and the database remains in a consistent state (consistency). The transaction is isolated from other concurrent transactions, so the customer's order cannot be affected by other customers' transactions (isolation). Finally, the transaction's updates to the order details are permanent, even if the website or the system crashes (durability).

1. Airline reservations: When a customer books a flight online, the transaction is treated as a single unit of work (atomicity). If the transaction is successful, the customer's booking is saved to the database, and the database remains in a consistent state (consistency). The transaction is isolated from other concurrent transactions, so the customer's booking cannot be affected by other customers transactions (isolation). Finally, the transaction's updates to the booking details are permanent, even if the website or the system crashes (durability).