The ACID transactions ensure that database transactions are reliable and consistent, even in the face of errors, power failures, or other problems. Atomicity ensures that all operations within a transaction are treated as a single unit of work, preventing inconsistencies by rolling back the entire transaction if any operation fails. Consistency ensures that the transaction brings the database from one valid state to another, following all rules and constraints defined in the database schema. Isolation ensures that concurrent transactions do not interfere with each other, executing as if it were the only transaction in the system. Durability ensures that committed changes are permanent and survive any subsequent failures by writing or persisting changes to disk or non-volatile storage. Optimistic locking allows multiple transactions to execute concurrently while verifying that data has not been modified by other transactions before committing changes. Eventual consistency allows data to be temporarily inconsistent while ensuring it will become consistent eventually through updates and distributed transactions. PostgreSQL supports ACID transactions, providing a reliable and widely used technique for database operations. To implement ACID transactions in PostgreSQL, one can use raw SQL or an Object-Relational Mapping (ORM) library like Sequelize, which provides a higher-level API for managing transactions. However, while ACID transactions ensure consistency and reliability, they can also have a performance impact, requiring careful management to minimize their effects.