Возникло исключение: 'System.Data.SqlClient.SqlException' in System.Data.dll проблема

---

ошибка:

Exception thrown: 'System.Data.SqlClient.SqlException' in System.Data.dll

Additional information: Cannot insert the value NULL into column 'Id', table 'Login.dbo.Rota'; column does not allow nulls. INSERT fails.

The statement has been terminated.

это в основном добавление пустых данных(NULL) в мою базу данных, когда этого не должно быть... я думаю

форма рис: http://postimg.org/image/skqp12obj/[^]

мой код:

        private void button2_Click(object sender, EventArgs e)
        {
            const string con = "Data Source = dqq5ndqef2.database.windows.net; Initial Catalog = Login; Integrated Security = False; User ID = richardjacobs97; Password = ********; Connect Timeout = 15; Encrypt = False; TrustServerCertificate = False; ApplicationIntent = ReadWrite; MultiSubnetFailover = False";

            using (SqlConnection connection = new SqlConnection(con))
            {
                connection.Open();

                using (SqlTransaction transaction = connection.BeginTransaction())
                using (SqlCommand cmd = new SqlCommand("INSERT INTO Rota (Id, Name, DateWorking) Values (@Id, @Name, @DateWorking)", connection, transaction))
                {
                    cmd.CommandType = CommandType.Text;

                    for (int i = 0; i < dataGridView1.Rows.Count; i++)
                    {
                        cmd.Parameters.Clear();

                            cmd.Parameters.AddWithValue("@Id", dataGridView1.Rows[i].Cells["Id"].Value);
                            cmd.Parameters.AddWithValue("@Name", dataGridView1.Rows[i].Cells["Name"].Value);
                            cmd.Parameters.AddWithValue("@DateWorking", dataGridView1.Rows[i].Cells["DateWorking"].Value);

                        cmd.ExecuteNonQuery();
                    }
                    transaction.Commit();
                }

                using (SqlCommand cmd = new SqlCommand("SELECT Id, Name, DateWorking FROM Rota", connection))
                {
                    DataTable dt = new DataTable();
                    SqlDataAdapter sda = new SqlDataAdapter(cmd);
                    sda.Fill(dt);
                    dataGridView1.DataSource = dt;
                }
            }
        }
    }
}

любой sugguestions?

---