What are the differences between isolation levels in databases?

What are the differences between isolation levels in databases?

Isolation levels define how transaction integrity is visible to other transactions. The main levels are Read Uncommitted, Read Committed, Repeatable Read, and Serializable.

Can you explain each isolation level briefly?

Sure!

1. Read Uncommitted: Allows dirty reads, meaning transactions can see uncommitted changes.
2. Read Committed: Prevents dirty reads; transactions only see committed changes.
3. Repeatable Read: Ensures that if a transaction reads a row, it will see the same data if it reads it again, preventing non-repeatable reads.
4. Serializable: The strictest level, it ensures complete isolation from other transactions, simulating serial execution.

What are the trade-offs of using a higher isolation level?

Higher isolation levels provide more consistency but can lead to increased locking and reduced concurrency, which may impact performance.

Which isolation level is generally recommended?

It depends on the application requirements. For most applications, Read Committed is a good balance between consistency and performance.