What negative phenomena do you know in SQL?

Dirty read. A transaction reads data that has not yet been committed by another transaction and may be rolled back.

Non-repeatable read. During a single transaction, when reading the same data again, its value appears different because another transaction has modified and committed it.

Phantom read. During a single transaction, when executing the query again with a selection condition, another transaction has added or removed rows satisfying this condition, resulting in a different number of rows.