An exclusive lock is a type of lock used in database management systems to control access to a resource, such as a record or a table. When a transaction holds an exclusive lock on a resource, no other transaction can read or write to that resource until the lock is released. This ensures that the data remains consistent and prevents conflicts during updates. Exclusive locks are essential for maintaining data integrity in multi-user environments. They are often used in conjunction with other locking mechanisms, such as shared locks, to balance the need for data access and the need for data protection. Proper use of exclusive locks helps prevent issues like deadlocks and data corruption.