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Which database isolation level prevents dirty reads but allows non-repeatable reads and phantom reads?
- Read Uncommitted
- Read Committed
- Repeatable Read
- Serializable
Answer: Read Committed
Read Committed isolation level ensures transactions see only committed data (prevents dirty reads). However, same query in same transaction may return different results if other transactions modify data (non-repeatable reads) or add new rows (phantom reads). Default in PostgreSQL and Oracle; balances consistency and concurrency.