Understanding Execution Context

Describes execution context and the login and user security tokens.

Understanding Context Switching

Describes how an execution context can be switched from one login or user to another for the purposes of impersonation.

EXECUTE AS vs. SETUSER

Compares and contrasts the EXECUTE AS statement and the SETUSER statement.

Using EXECUTE AS to Create Custom Permission Sets

Describes how to define custom permission sets using EXECUTE AS inside a module.

Extended Database Impersonation by Using EXECUTE AS

Describes how to use EXECUTE AS to extend user impersonation beyond the scope of the current database.

Using EXECUTE AS in Modules

Describes how to use EXECUTE AS inside modules such as stored procedures, triggers, queues, and user-defined functions.