问试图通过c#控制台更新sql数据库中的特定值

EN

        Console.WriteLine("Which time would you like to edit for group {0}?",newGroup);
        string ClassTime = Console.ReadLine();
        Console.WriteLine("Enter the current teacher and classroom for {0}",newGroup);
        string teacherandclassroom = Console.ReadLine();
        Console.WriteLine(string.Format("Enter the new teacher and classroom number for group {0} at {1} ",newGroup,ClassTime));
        string newTeacherClassRoom = Console.ReadLine();
        SQLCONN.Open();
        using (SqlCommand cmd1 =
           new SqlCommand("UPDATE mondayTable SET " + ClassTime +" =@"+ClassTime + " WHERE " + ClassTime + "@=" + teacherandclassroom, SQLCONN)) //or WHERE newGroup?
        {
            cmd1.Parameters.AddWithValue("@" + ClassTime, newTeacherClassRoom);
            cmd1.Parameters.AddWithValue("@" + teacherandclassroom, teacherandclassroom);
            cmd1.ExecuteNonQuery();
            Console.WriteLine("Database Updated...");
        }
        Console.ReadKey();

CREATE TABLE [dbo].[mondayTable] (
[SAT]         VARCHAR(50)           NOT NULL,
[09:00-09.40] VARCHAR (MAX) NULL,
[10:10-10:50] VARCHAR (MAX) NULL,
[11.00-11:40] VARCHAR (MAX) NULL,
[11:50-12:30] VARCHAR (MAX) NULL,
[12:40-13:20] VARCHAR (MAX) NULL,
[13:30-14:10] VARCHAR (MAX) NULL,
[14:20-15:00] VARCHAR (MAX) NULL,
[15:10-15:50] VARCHAR (MAX) NULL,
[16:00-16:40] VARCHAR (MAX) NULL,
[16:50-17:30] VARCHAR (MAX) NULL,
[17:40-18:20] VARCHAR (MAX) NULL,
[18:30-19:10] VARCHAR (MAX) NULL,
[19:20-20:00] VARCHAR (MAX) NULL,
PRIMARY KEY CLUSTERED ([SAT] ASC)
);