Database

public void WriteTable(DataTable table)
{
  //First, I create a column string to use in the CREATE TABLE sql statement.
  string columnString="";
 
  foreach(DataColumn column in table.Columns)
  {
    string type = "";

    switch(column.DataType.ToString())
    {
      case "System.String":
        type = "varchar(" + MaxLength(column) + ")";
        break;
      case "System.Int32":
        type = "int";
        break;
      case "System.Double":
        type = "double";
        break;
      default:
        throw new ArgumentException("Data type not found.", column.DataType.ToString());
    }

    columnString += column.ColumnName + " " + type + ", ";
  }


  columnString = columnString.Substring(0, columnString.Length-2);
  //Done creating column string.
  //////////////////////////////////////////////////////////////////////
  
  //Second, I create the new table on disk.
  connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + directory + ";Extended Properties=dBase IV";
  sqlString = "CREATE TABLE " + name + " (" + columnString + ")";
  connection = new OleDbConnection(connectionString);
  command = new OleDbCommand(sqlString, connection);
			
  command.Connection.Open();
  command.ExecuteNonQuery();
  command.Connection.Close();
  //Done creating table.
  //////////////////////////////////////////////////////////////////////
  
  //Third, I insert each record into the new table.
  command.Connection.Open();

  int columnCount = table.Columns.Count;
  foreach(DataRow row in table.Rows)
  {
    string valueString="";
    for(int i=0; i < columnCount; i++)
    {
      switch(row[i].GetType().ToString())
      {
        case "System.String":
          valueString += "'" + ((string)row[i]).Replace("'", "''") + "', ";
          break;
        case "System.Int32":
          valueString += System.Convert.ToString((int)row[i]) + ", ";
          break;
        case "System.Double":
          valueString += System.Convert.ToString((double)row[i]) + ", ";
          break;
        case "System.DBNull":
          valueString += "'', ";
          break;
        default:
          throw new ArgumentException("Data type not found.", row[i].GetType().ToString());
      }
    }
    valueString = valueString.Substring(0, valueString.Length-2);
    sqlString = "INSERT INTO " + name + " VALUES (" + valueString + ")";
    command.CommandText = sqlString;
    command.ExecuteNonQuery();
  }


  command.Connection.Close();

}