No Dirty Reads: Everything you always wanted to know about SQL isolation levels (but were too afraid to ask)

Database transaction isolation levels determine how much concurrent data modification is allowed during a single transaction in order to maintain consistency and accuracy. The four main types are Read Uncommitted, Read Committed, Repeatable Read, and Serializable. - Read Uncommitted: This is the lowest level of isolation that allows dirty reads (reading uncommitted data). It may result in non-repeatable reads or phantom reads. - Read Committed: This level prevents dirty reads but can still cause non-repeatable reads and phantom reads. It is a common default setting for many databases. - Repeatable Read: This intermediate level ensures that if the same data is read twice within the same transaction, it will return the same result each time. However, changes to other rows can still occur between these reads. - Serializable: This highest level of isolation guarantees complete consistency by treating transactions as atomic operations that must be completed in full or not at all. It prevents dirty reads, non-repeatable reads, and phantom reads but may cause more transaction conflicts and retries due to its strictness. Choosing the right transaction isolation level depends on the specific needs of your application. Factors such as concurrency requirements, data consistency demands, and potential for anomalies should all be considered when making this decision.