DBMS: Lock/Locking (Definitions)

"The process of restricting access to resources in a multi-user environment to maintain security and prevent concurrent access problems. SQL Server automatically applies locks to tables or pages." (Karen Paulsell et al, "Sybase SQL Server: Performance and Tuning Guide", 1996)

"SQL Server issues locks to prevent users from interfering with each other's work." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"A restriction on access to a resource in a multiuser environment. SQL Server locks users out of a specific record, field, or file automatically to maintain security or prevent concurrent data manipulation problems." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A method the DBMS uses to prevent concurrent transactions from interfering with one another. Physically, a lock is one of three things: a latch, a mark on the wall, or a RAM record." (Peter Gulutzan & Trudy Pelzer, "SQL Performance Tuning", 2002)

"A method of ensuring concurrency. Locking enables users to temporarily "check out" an object, preventing other users from changing the object, for the purpose of ensuring consistency." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"SQL Server uses locks to prevent multiple users from modifying the same data at the same time." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"A mechanism used by a concurrent system to prevent data anomalies by isolating transactions from each other." (Marilyn Miller-White et al, "MCITP Administrator: Microsoft® SQL Server™ 2005 Optimization and Maintenance 70-444", 2007)

"A lock is an access restriction placed on part of a database to prevent other users or processes from viewing or modifying data as it is being viewed or modified by one process. Locks can be placed on rows, pages, extents, tables, or databases." (Darril Gibson, "MCITP SQL Server 2005 Database Developer All-in-One Exam Guide", 2008)

"MongoDB uses locks to ensure that concurrency does not affect correctness. MongoDB uses read locks, write locks and intent locks. For more information, see What type of locking does MongoDB use?." (MongoDb, "Glossary", 2008)

"Used to control access to part of the database. For example, while one user updates a row, the database places a lock on the row so other users cannot interfere with the update. Different databases may lock data by rows, table, or disk page." (Rod Stephens, "Beginning Database Design Solutions", 2008)

"The processing of giving a transaction exclusive rights to view and/or update a database element to prevent problems that arise with interleaved transaction execution." (Jan L Harrington, "SQL Clearly Explained 3rd Ed. ", 2010)

"A DBMS function used to ensure the integrity of data. When a database resource is locked by one process, another process is not permitted to change the locked data. Locking is necessary to enable the DBMS to facilitate the ACID properties of transaction processing." (Craig S Mullins, "Database Administration: The Complete Guide to DBA Practices and Procedures" 2nd Ed, 2012)

"A restriction on access to a resource in a multiuser environment." (Microsoft, "SQL Server 2012 Glossary", 2012)

"A means of preventing uncommitted changes made by one application process from being perceived by another application process and for preventing one application process from updating data that is being accessed by another process. A lock ensures the integrity of data by preventing concurrent users from accessing inconsistent data. A means of serializing a sequence of events or serializing access to data." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)

"The process by which a DBMS restricts access to a row in a multiuser environment. The DBMS usually sets a bit on a row or the physical page containing a row that indicates the row or page is locked." (Microsoft)