This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Isolation means that no operation outwith the scope of the current transaction can see data in an intermediate state. Basically, if a transaction is updating a row, no other transaction can see that update till it has completed.