IF EXISTS (SELECT * FROM sys.database_principals WHERE name = alias'')
DROP USER [alias]
GO
CREATE USER [DEV] FOR LOGIN [alias]
GO
EXEC sp_addrolemember ''db_datareader'', alias''
Go
DROP USER [alias]
GO
CREATE USER [DEV] FOR LOGIN [alias]
GO
EXEC sp_addrolemember ''db_datareader'', alias''
Go