Database locking is a mechanism used in database management systems to control access to data. When a user wants to modify data, the system locks that data to prevent other users from making changes simultaneously. This ensures data integrity and consistency, as it avoids conflicts that could arise from multiple users trying to update the same information at the same time. There are different types of locks, such as exclusive locks and shared locks. An exclusive lock allows only one user to modify the data, while a shared lock permits multiple users to read the data but not change it. These locking strategies help maintain order and reliability in transaction processing.