Atomicity - Design a Reliable Wallet Transfer System with ACID Guarantees

Atomicity in Action: Designing a Reliable Wallet Transfer System with ACID Guarantees Building a wallet system like PhonePe, GPay, or Paytm requires strict data consistency. Even a small error can lead to money loss, duplicate transactions, or incorrect balances. This is why ACID properties, especially Atomicity, are critical in such systems. Atomicity ensures that all operations in a transaction are completed successfully. If any step fails, the entire transaction is rolled back, and the database remains unchanged. CREATE TABLE accounts ( id SERIAL PRIMARY KEY, name TEXT NOT NULL, balance INT NOT NULL CHECK (balance >= 0), last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP ); Insert sample data: INSERT INTO accounts (name, balance) VALUES ('Alice', 1000), ('Bob', 500); Initial state of the table: ID Name Balance 1 Alice 1000 2 Bob 500 Successful Transaction Transfer 200 from Alice to Bob using a transaction: UPDATE accounts SET balance = balance - 200 WHERE name = 'Alice'; UPDATE accoun