Какова роль уровня изоляции транзакций Repeatable Read в обеспечении согласованности данных?

The Repeatable Read transaction isolation level guarantees that within a single transaction, all repeated reads of the same data will return the same values. This prevents the phenomenon of "non-repeatable reads," where data can change between two reads within the same transaction. Thus, Repeatable Read ensures data consistency by locking changes made by other transactions at the level of read rows until the current transaction completes. However, it does not always prevent phantom reads (the appearance of new rows), for which the Serializable level is required.