Security5：Execute AS 和 impersonate 权限

USE db_study;
GO

--Create two temporary principals
CREATE LOGIN login1 
WITH PASSWORD = ‘123‘
,DEFAULT_DATABASE=db_study
,CHECK_EXPIRATION=off
,CHECK_POLICY=off;
go

CREATE LOGIN login2
WITH PASSWORD = ‘123‘
,DEFAULT_DATABASE=db_study
,CHECK_EXPIRATION=off
,CHECK_POLICY=off;
go


CREATE USER user1 
FOR LOGIN login1
with default_schema=dbo;
GO

CREATE USER user2 
FOR LOGIN login2
with default_schema=dbo;
GO


--Give IMPERSONATE permissions on user2 to user1
--so that user1 can successfully set the execution context to user2.
GRANT IMPERSONATE 
ON USER:: user2 
TO user1;
GO


--Display current execution context.
SELECT SUSER_NAME(), USER_NAME();


-- Set the execution context to login1. 
EXECUTE AS LOGIN = ‘login1‘;
--Verify the execution context is now login1.
SELECT SUSER_NAME(), USER_NAME();

--Login1 sets the execution context to login2.
EXECUTE AS USER = ‘user2‘;
--Display current execution context.
SELECT SUSER_NAME(), USER_NAME();


-- The execution context stack now has three principals: the originating caller, login1 and login2.
--The following REVERT statements will reset the execution context to the previous context.
REVERT;
--Display current execution context.
SELECT SUSER_NAME(), USER_NAME();


REVERT;
--Display current execution context.
SELECT SUSER_NAME(), USER_NAME();

--Remove temporary principals.
DROP LOGIN login1;
DROP LOGIN login2;
DROP USER user1;
DROP USER user2;
GO