What is a LOCK?
A lock in MySQL is a mechanism used to control access to data when multiple users or processes are working with the database simultaneously. It ensures that only one transaction can modify or read certain data at a time, preventing issues like inconsistent results, lost updates, or data corruption. Locks are essential for maintaining data integrity in multi-user environments, such as e-commerce sites or banking systems.
MySQL automatically applies locks during transactions, but you can also manage them manually. There are different types of locks, such as row-level and table-level, depending on the scope of data access. InnoDB, the default MySQL storage engine, supports fine-grained row-level locking for better performance. Proper use of locks ensures that operations remain reliable and safe even under heavy database activity.