CREATE TABLE [dbo].[User]( [UserId] [uniqueidentifier] NOT NULL, [Login] [nvarchar](15) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [Password] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [FirstName] [nvarchar](30) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [LastName] [nvarchar](30) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, CONSTRAINT [PK_User] PRIMARY KEY CLUSTERED ( [UserId] ASC )WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY] ) ON [PRIMARY]I would like to make the Login column unique.