Duplicate multiple row insert and update in datagridview

im insert and update data in datagridview but it inserted multiple duplicate rows in table at same time when i updated one row it updated all row actually im not understanding where i done mistake im providing you my insert code and update code if it is possible give me modify code 
insert code i written : dataGridView1_RowLeave event and Updated Code i written : dataGridView1_CellValueChanged 

private void dataGridView1_RowLeave(object sender, DataGridViewCellEventArgs e)
      {
          string connectionString = null;
          connectionString = ConfigurationManager.ConnectionStrings["AccessConnectionString"].ConnectionString;
          con.ConnectionString = connectionString;

          string cmd1 = "insert into Ledger([AccountNumber],[Account],[Date],[Description],[Post_Ref],[Debit],[Credit],[Balance])values(?,?,?,?,?,?,?,?)";
          OleDbCommand cmd = new OleDbCommand(cmd1, con);
          con.Open();
          cmd.CommandType = CommandType.Text;



          int accountNumber;

          bool accountHasValue = int.TryParse(dataGridView1.Rows[e.RowIndex].Cells["AccountNumber"].Value.ToString(), out accountNumber);

          if (accountHasValue)
          {
              cmd.Parameters.AddWithValue("@AccountNumber", accountNumber);
          }
          else
          {
              cmd.Parameters.AddWithValue("@AccountNumber", DBNull.Value);
          }

          string accounts = dataGridView1.Rows[e.RowIndex].Cells["Account"].Value.ToString();
          cmd.Parameters.AddWithValue("@Account", accounts);

          DateTime datetime;
          bool dateTimeHasValue = DateTime.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Date"].Value.ToString(), out datetime);

          if (dateTimeHasValue)
          {
              cmd.Parameters.AddWithValue("@Date", datetime);
          }
          else
          {
              cmd.Parameters.AddWithValue("@Date", DBNull.Value);
          }


          string Description = dataGridView1.Rows[e.RowIndex].Cells["Description"].Value.ToString();
          cmd.Parameters.AddWithValue("@Description", Description);


          string Post_Ref = dataGridView1.Rows[e.RowIndex].Cells["Post_Ref"].Value.ToString();
          cmd.Parameters.AddWithValue("@Post_Ref", Post_Ref);


          int debit;
          bool debitHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Debit"].Value.ToString(), out debit);

          if (debitHasValue)
          {
              cmd.Parameters.AddWithValue("@Debit", debit);
          }
          else
          {
              cmd.Parameters.AddWithValue("@Debit", DBNull.Value);
          }


          int Credits;
          bool CreditsHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Credit"].Value.ToString(), out Credits);

          if (CreditsHasValue)
          {
              cmd.Parameters.AddWithValue("@Credit", Credits);
          }
          else
          {
              cmd.Parameters.AddWithValue("@Credit", DBNull.Value);
          }

          int Balances;
          bool BalancesHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Balance"].Value.ToString(), out Balances);

          if (BalancesHasValue)
          {
              cmd.Parameters.AddWithValue("@Balance", Balances);
          }
          else
          {
              cmd.Parameters.AddWithValue("@Balance", DBNull.Value);
          }

          cmd.ExecuteNonQuery();
          con.Close();

      }

private void dataGridView1_CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {
            string connectionString = null;
            connectionString = ConfigurationManager.ConnectionStrings["AccessConnectionString"].ConnectionString;
            con.ConnectionString = connectionString;



            string cmd1 = "update Ledger set [AccountNumber]=@AccountNumber,[Account]=@Account,[Date]=@Date,[Description]=@Description,[Post_Ref]=@Post_Ref,[Debit]=@Debit,[Credit]=@Credit,[Balance]=@Balance where AccountNumber=@AccountNumber";
             OleDbCommand cmd = new OleDbCommand(cmd1, con);
             con.Open();
             cmd.CommandType = CommandType.Text;
             int accountNumber;

             bool accountHasValue = int.TryParse(dataGridView1.Rows[e.RowIndex].Cells["AccountNumber"].Value.ToString(), out accountNumber);

             if (accountHasValue)
             {
                 cmd.Parameters.AddWithValue("@AccountNumber", accountNumber);
             }
             else
             {
                 cmd.Parameters.AddWithValue("@AccountNumber", DBNull.Value);
             }

             string accounts = dataGridView1.Rows[e.RowIndex].Cells["Account"].Value.ToString();
             cmd.Parameters.AddWithValue("@Account", accounts);

             DateTime datetime;
             bool dateTimeHasValue = DateTime.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Date"].Value.ToString(), out datetime);

             if (dateTimeHasValue)
             {
                 cmd.Parameters.AddWithValue("@Date", datetime);
             }
             else
             {
                 cmd.Parameters.AddWithValue("@Date", DBNull.Value);
             }


             string Description = dataGridView1.Rows[e.RowIndex].Cells["Description"].Value.ToString();
             cmd.Parameters.AddWithValue("@Description", Description);


             string Post_Ref = dataGridView1.Rows[e.RowIndex].Cells["Post_Ref"].Value.ToString();
             cmd.Parameters.AddWithValue("@Post_Ref", Post_Ref);


             int debit;
             bool debitHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Debit"].Value.ToString(), out debit);

             if (debitHasValue)
             {
                 cmd.Parameters.AddWithValue("@Debit", debit);
             }
             else
             {
                 cmd.Parameters.AddWithValue("@Debit", DBNull.Value);
             }


             int Credits;
             bool CreditsHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Credit"].Value.ToString(), out Credits);

             if (CreditsHasValue)
             {
                 cmd.Parameters.AddWithValue("@Credit", Credits);
             }
             else
             {
                 cmd.Parameters.AddWithValue("@Credit", DBNull.Value);
             }

             int Balances;
             bool BalancesHasValue = Int32.TryParse(dataGridView1.Rows[e.RowIndex].Cells["Balance"].Value.ToString(), out Balances);

             if (BalancesHasValue)
             {
                 cmd.Parameters.AddWithValue("@Balance", Balances);
             }
             else
             {
                 cmd.Parameters.AddWithValue("@Balance", DBNull.Value);
             }

             cmd.ExecuteNonQuery();
             con.Close();

        }