Answer
A dirty read occurs when one transaction reads data written but not committed by another transaction. • The writer could still roll back that value. • SQL isolation levels describe whether this anomaly is allowed. • PostgreSQL does not permit dirty reads, even at Read Uncommitted.
💡 SQL Example
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
Result
SET
⚡ Quick Revision
A dirty read observes another transaction’s uncommitted data.