beginnerIsolation Levels — Dirty Read, Phantom Read, Non-Repeatable Read

What are the three main read anomalies in database transactions?

Dirty Read: reading data that another transaction has written but not yet committed. If that transaction rolls back, you've read data that never officially existed. Prevented at READ COMMITTED. Non-Repeatable Read: within a single transaction, reading the same row twice returns different values because another transaction committed a change between reads. Prevented at REPEATABLE READ. Phantom Read

Ready to master this question?

Generate a complete walkthrough — background, the full answer in plain language, a working code example explained line by line, a real-world scenario, common mistakes, and how this same question gets asked in different ways.

Sign in to generate a response

Next Step

Continue to What is the difference between READ COMMITTED and REPEATABLE READ?← Back to all SQL questions