a dirty read refers to a situation where one transaction reads data from a database that has been modified by another ongoing transaction but has not yet been committed or rolled back. This phenomenon occurs in concurrent database operations, where multiple transactions can access and modify the same data simultaneously. The sequence of events in a dirty read scenario is as follows: Transaction A reads a value from a data item in the database. Transaction B updates the same data item but has not committed the changes yet. Transaction A reads the modified value (dirty data) before Transaction B has finished and committed its changes. The problem with dirty reads is that Transaction A may obtain and act upon inaccurate or inconsistent data, which may lead to incorrect results or decisions. Dirty reads can cause data integrity issues and are generally considered undesirable in a database system.