Lock (database)

A lock, as a read lock or write lock, is used when multiple users need to access a database concurrently. This prevents data from being corrupted or invalidated when multiple users try to read while others write to the database. Any single user can only modify those database records (that is, items in the database) to which they have applied a lock that gives them exclusive access to the record until the lock is released. Locking not only provides exclusivity to writes but also prevents (or controls) reading of unfinished modifications (AKA uncommitted data).