A Ruby class to acces an Oracle database

oracle_reader.rb

################################################################################
require 'oci8'
require 'iconv'

################################################################################
class OracleReader
  ################################################################################
  def initialize(server, username, password)
    # Open the connection.
    @connection = OCI8.new(username, password, server)
  end

  ################################################################################
  def query(sql_select, options = {})
    self.class.get_query_default_options(options)
    
    cursor  = @connection.exec(sql_select)
    rows    = []
  
    begin
      while (row = cursor.fetch_hash)
        row.each do |key, value|
          row[key] = value.read if options[:preload_clobs] && value.is_a?(OCI8::CLOB)
        end

        rows << row
      end
    ensure
      cursor.close
    end

    rows.map { |row|
      row.inject Hash.new do |memo, column|
        memo[column[0].downcase] = 
            case column[1]
              when OraDate  then  ruby_date_with_timezone_support(column[1]) 
              when String   then  options[:encoding_to_from] ? Iconv.conv(options[:encoding_to_from][0], options[:encoding_to_from][1], column[1]) : column[1]
              else                column[1]
            end

        memo
      end
    }.map(&:symbolize_keys!)
  end

  ################################################################################
  def close
    # Close the connection.
    @connection.logoff
  end

  ################################################################################
  # Given a username, password, Oracle DB URL (e.g. '//172.16.202.191:1521/SITES')
  # and a SQL select string, this method performs a query and returns an array 
  # with the resulting rows. Each entry in this array is a hash with column names 
  # transformed into symbols as keys. For example:
  #
  #   >> sql = 'SELECT c.txt_titulo_conteudo AS title FROM pwa_adm.conteudo c WHERE c.dat_inc >= (SYSDATE-2)'
  #   >> data = OracleReader.connect_and_query('//172.16.202.191:1521/SITES', 'ANL_ABD', 'ANL_ABD', sql)
  #   >> data[16][:title] # => "Toyota tem lucro maior e eleva estimativas mesmo com recall"
  def self.connect_and_query(server, username, password, sql_select, options = {})
    get_query_default_options(options)
    
    connection = self.new(server, username, password)
   
    begin
      connection.query(sql_select, options)
    ensure
      connection.close
    end
  end

  ################################################################################
  protected
  
  ################################################################################
  def ruby_date_with_timezone_support(oracle_date)
    Time.zone.local(oracle_date.year, oracle_date.month, oracle_date.day, oracle_date.hour, oracle_date.minute, oracle_date.second)
  end

  ################################################################################
  def self.get_query_default_options(options)
    options.reverse_merge!(
      :encoding_to_from => nil,
      :preload_clobs    => true
    )
  end
end