Business Analyst: What is a database transaction?

Transaction — unit of work that is atomic.

ACID properties:

• Atomicity — all or nothing.
• Consistency — valid state.
• Isolation — concurrent execution.
• Durability — permanent changes.

Example:

1BEGIN TRANSACTION;
2
3UPDATE accounts SET balance = balance - 100 WHERE id = 1;
4UPDATE accounts SET balance = balance + 100 WHERE id = 2;
5
6COMMIT; -- or ROLLBACK on error

BA relevance:

• Understand data integrity.
• Write requirements for transactions.
• Error handling.