Listing 1 : Code qui montre l’importance des SID

sp_grantdbaccess guest
GO
CREATE VIEW [dbo].[MyView] AS
SELECT [Column1] FROM [Database1].[dbo].[MyTable]
GO
GRANT SELECT ON [Database2].[dbo].[MyView] TO PUBLIC
GO

–Illustrate behavior with different database owners.
PRINT ‘** Note different logins/SIDs for dbo users so the select
fails **’
EXEC Database1..sp_helpuser ‘dbo’
EXEC Database2..sp_helpuser ‘dbo’
SETUSER ‘guest’

–Select permission denied because of broken ownership chain.
SELECT * FROM [Database2].[dbo].[MyView]
SETUSER
GO

–Change Database2 ownership to match Database1.
EXEC sp_changedbowner ‘DatabaseOwner1’
GO

–Illustrate behavior with same database owner.
PRINT ‘** Note same login/SID for dbo users so the select now succeeds
**’
EXEC Database1..sp_helpuser ‘dbo’
EXEC Database2..sp_helpuser ‘dbo’
SETUSER ‘guest’

–Select succeeds because ownership chain is unbroken.
SELECT * FROM [Database2].[dbo].[MyView]
SETUSER
GO