Chapter 14
Locking is a crucial function of any multiple-user database system, including Microsoft SQL Server. As you know, SQL Server manages multiple users simultaneously and ensures that all transactions observe the properties of the specified isolation level. At the highest isolation level, Serializable, SQL Server must make the multiple-user system yield results that are indistinguishable from those of a single-user system. It does this by automatically locking data to prevent changes made by one user from unexpectedly affecting work being done by another user on the same database at the same time.