NotGoogleKeep.txt

            DataTable rs = new DataTable();

            using (var odConnection = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\Users\IIG\Desktop\test.xlsx;Extended Properties='Excel 12.0;HDR=YES;IMEX=1;';"))
            {
                odConnection.Open();

                using (OleDbCommand cmd = new OleDbCommand())
                {
                    cmd.Connection = odConnection;
                    cmd.CommandType = CommandType.Text;
                    cmd.CommandText = "SELECT * FROM [Sheet2$]";
                    using (OleDbDataAdapter oleda = new OleDbDataAdapter(cmd))
                    {
                        oleda.Fill(rs);
                    }
                }
                odConnection.Close();
            }
            foreach(DataRow row in rs.Rows)
            {
                foreach(object item in row.ItemArray)
                {
                    Console.Write(item +"\t");
                }
                Console.WriteLine();
            }
        }

Usable!

public string InsertWithParams(string sql, List colValue, List cols, out string error)
{
error = "";
try
{
OracleConnection con = new OracleConnection("Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=)(PORT=)))(CONNECT_DATA=(SERVER=DEDICATED)(SID=)));User Id=;Password=");
OracleCommand command = new OracleCommand(sql, con);
for (int i = 0; i < colValue.Count; i++)
{
command.Parameters.Add(new OracleParameter(cols[i], colValue[i]));
}
command.ExecuteNonQuery();
command.Connection.Close();
}
catch (Exception ex)
{
error = ex.Message;
}
return null;
}

AND

public int DataTableToTable(DataTable dt,out string error)
{
error = "";
string finalSql = "";
List colValue = new List();
List cols = new List() {"COLUMN1","COLUMN2","COLUMN3"};
for (int i = 0; i < dt.Rows.Count; i++)
{
finalSql = "INSERT INTO TABLENAME(COLUMN1,COLUMN2,COLUMN3) VALUES(:COLUMN1,:COLUMN2,:COLUMN3) ";
for (int j = 0; j < dt.Columns.Count; j++)
{
colValue.Add(dt.Rows[i][j].ToString());
}
objDAL.InsertWithParams(finalSql,colValue,cols, out error);
if (error != "")
return error;
inserts++;
colValue.Clear();
}
}

Transactions:

      OracleTransaction trans = con.BeginTransaction();              
      try
      {
          error = "";
          OracleCommand cmd = new OracleCommand();
          cmd.Transaction = trans;
          cmd.Connection = con;
          cmd.CommandText = query;
          rowsInserted = cmd.ExecuteNonQuery();
          trans.Commit();
          con.Dispose();
          return rowsInserted;
      }
      catch (Exception ex)
      {
          trans.Rollback();
          error = ex.Message;
          rowsInserted = 0;
      }

public void Fillcombo()
{
string oradb = " Data Source=xe;User Id=dbname;Password=pws; ";
string query = "select id , name from table";
OracleConnection condatabase = new OracleConnection(oradb);
OracleCommand cmddatabase = new OracleCommand(query, condatabase);

        try
        {
            condatabase.Open();
            OracleDataReader myReader = cmddatabase.ExecuteReader(); ;
            myReader = cmddatabase.ExecuteReader();
            while (myReader.Read())
            {
                string sname = myReader.GetInt32(0).ToString();
                comboBox1.Items.Add(sname.ToString());
            }

        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }