public string CreateMahasiswa(Mahasiswa mhs)
        {
            string msg = "Gagal";

            sqlConnection = new SqlConnection(connectionString);
            string     query = string.Format("Insert into dbo.Mahasiswa values ('{0}', '{1}', '{2}', '{3}')", mhs.nama, mhs.nim, mhs.prodi, mhs.angkatan);
            SqlCommand cmd   = new SqlCommand(query, sqlConnection);

            try
            {
                sqlConnection.Open();
                Console.WriteLine(query);
                cmd.ExecuteNonQuery();
                sqlConnection.Close();
                msg = "Sukses";
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.WriteLine(query);
            }
            return(msg);
        }