Final answer:
Concurrency control issues arise when operations from two transactions on the same database items are interleaved improperly, leading to potential data integrity problems. Databases use various protocols and mechanisms to manage these issues and maintain consistency.
Step-by-step explanation:
When two transactions that access the same database items have their operations interleaved in a way that makes the value of some database item incorrect, this is known as a concurrency control issue. Concurrency control is critical in database management systems to ensure the integrity and consistency of data. If not managed correctly, interleaved transactions can lead to problems such as dirty reads, non-repeatable reads, and phantom reads. These issues can cause incorrect data to be read or written, leading to potential faults in the database system. In order to manage such issues, databases employ various concurrency control mechanisms like lock-based protocols, timestamp-based protocols, or multiversion concurrency control to prevent transactions from interfering with each other and ensure that operations are carried out in a way that maintains data consistency and integrity.