Could you explain what is meant by the problem of dirty reads in the context of working with databases?

The dirty read problem occurs when one transaction reads data that has been modified by another transaction but not yet committed. If the second transaction rolls back, the first transaction has received incorrect, 'dirty' data.

For example:

1. Transaction A modifies a value in the database but does not commit.
2. Transaction B reads this modified value.
3. Transaction A rolls back, canceling the changes.

As a result, Transaction B operates on data that does not actually exist in the database, which can lead to errors and inconsistency.

To prevent dirty reads, transaction isolation levels are used, such as READ COMMITTED, which prohibits reading uncommitted changes from other transactions.