Chapter 9. Transactions and Concurrency

This chapter covers transactions and their properties and describes how Microsoft SQL Server handles users who are concurrently trying to access the same data. I explain how SQL Server uses locks to isolate inconsistent data, how you can troubleshoot blocking situations, and how you can control the level of consistency when you are querying data with isolation levels. This chapter also covers deadlocks and ways to mitigate their occurrence.


A transaction is a unit of work that might include multiple activities that query and modify data and that can also change data definition.

You can define transaction boundaries either explicitly or implicitly. You define the beginning of a transaction explicitly ...

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