Can you list the requirements for a transactional system (ACID)? Where have you used transactions in your work?

The requirements for transactional systems are described by the ACID principles:

• Atomicity: a transaction is completed in full or not at all. If one part of the operation fails, all changes are rolled back.
• Consistency: after the transaction completes, the data remains in a correct state, satisfying all rules and constraints.
• Isolation: parallel transactions do not affect each other, and the results of one transaction are not visible to others until it is completed.
• Durability: after a transaction is committed, its changes are saved and not lost even in case of failures.

In my work, I used transactions when working with databases to ensure data integrity. For example, when placing an order in an online store, a transaction guarantees that the deduction of goods from the warehouse and the creation of the order record happen simultaneously — either both actions are performed, or neither.