DBMS: Shared Lock (Definitions)

 "A lock created by non-update ('read') operations. Other users may read the data concurrently, but no transaction can acquire an exclusive lock on the data until all the shared locks have been released." (Karen Paulsell et al, "Sybase SQL Server: Performance and Tuning Guide", 1996)

"A lock used during READ operations." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"Lock that allows concurrent transactions to read a resource." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"Control over a portion of the database given to one or more transactions that prevents other transactions from modifying the data while the locks are in place." (Jan L Harrington, "Relational Database Design and Implementation" 3rd Ed., 2009)

"A lock on a database element that prevents other transactions from updating the database element while the lock is held." (Jan L Harrington, "SQL Clearly Explained" 3rd Ed., 2010)

"A lock that is issued when a transaction requests permission to read data from a database and no exclusive locks are held on that data by another transaction. A shared lock allows other read-only transactions to access the database." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)

"A lock created by non-update (read) operations." (SQL Server 2012 Glossary, "Microsoft", 2012)

"The type of lock taken by the DBMS when data is read with no intent to update it." (Craig S Mullins, "Database Administration", 2012)

"A lock that limits concurrently running application processes to read-only operations on database data." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)