Database locking & database isolation levels

Database locking and isolation are essential concepts for managing concurrent transactions and ensuring data integrity in SQL databases. As user volume increases, applications face challenges like dirty reads, non-repeatable reads, and phantom reads, which can lead to incorrect data being displayed. To address these issues, databases adhere to ACID principles and employ various isolation levels, including READ_UNCOMMITTED, READ_COMMITTED, REPEATABLE_READ, and SERIALIZABLE, each offering different levels of data protection and concurrency control. While locks help prevent data anomalies, they can also introduce problems such as lock contention, long-term blocking, and deadlocks, which can hinder application performance. Understanding these mechanisms is crucial for developers who aim to scale applications efficiently while maintaining data consistency.