Paul White

SQL Server Isolation Levels : A Series

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Itzik is a T-SQL trainer, a co-founder of SolidQ, and blogs about T-SQL fundamentals and query tuning.

Itzik’s Posts Credit : Alexander Baxevanis

Updated April 23, 2015

Last year, I put together a string of posts aimed at taking a detailed look at concurrency, the ACID properties of statements and transactions, and each of the major isolation levels in SQL Server. Now I have concluded the series with a final post on probably the most common intentionally-used isolation level: read uncommitted ("NOLOCK").

The ACID Properties of Statements & Transactions
The Serializable Isolation Level
The Repeatable Read Isolation Level
The Read Committed Isolation Level
Read Committed Snapshot Isolation
Data Modifications under Read Committed Snapshot Isolation
The SNAPSHOT Isolation Level
The Read Uncommitted Isolation Level


Since you've been patient for the final installment, there is some other background reading/watching on read uncommitted that I can offer: