Question

What is a potential problem with lower isolation levels?

1) Dirty reads
2) Non-repeatable reads
3) Phantom reads
4) Lost updates

Answer 1

Lower isolation levels in database transactions can lead to potential problems such as dirty reads, non-repeatable reads, phantom reads, and lost updates, all of which can affect the integrity of the data.

Step-by-step explanation:

A potential problem with lower isolation levels in database transactions is dirty reads, which occur when a transaction reads data that has not been committed and may be rolled back. Another issue is non-repeatable reads, this happens when a transaction reads the same row twice and gets different data each time because another transaction has modified the data in between the reads. Furthermore, phantom reads can occur, where a transaction re-executes a query returning a set of rows that satisfies a certain condition and finds that the set of rows has changed due to another recently committed transaction. Lastly, lost updates may also happen, which involve a scenario where two concurrent transactions both update a row, and one of the updates is overwritten by the other. These problems can compromise the integrity of data within a database.