What is the role of each isolation level in a database?
sobes.tech AI
Answer from AI
Transaction isolation levels determine how data modifications made by one transaction are visible to other transactions, and help control concurrency issues:
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READ UNCOMMITTED — the lowest isolation level. Allows reading uncommitted data (dirty reads). Can lead to inconsistent data.
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READ COMMITTED — guarantees that a transaction only sees committed data. Prevents dirty reads but allows non-repeatable reads.
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REPEATABLE READ — ensures that data read at the beginning of a transaction will not change until it ends. Prevents non-repeatable reads but allows phantom reads.
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SERIALIZABLE — the strictest level. Transactions execute as if they were sequential, preventing all anomalies but reducing concurrency and performance.
The choice of isolation level depends on the application's requirements for consistency and performance.