gistfile1.rb

require 'rubygems'
require 'active_record'

class Contact < ActiveRecord::Base
 
  begin
    establish_connection(:adapter => 'mysql',
                         :database => 'contacts',
                         :host => '127.0.0.1',
                         :username => 'root',
                         :password => '')
  rescue Exception => error
     STDERR.puts error
  end
  
  def self.add_contact(name, address, tel, email)
    begin
      c = Contact.new(:name => name, :address => address, :tel => tel, :email => email)
      c.save
    rescue 
      STDERR.puts 'Must specify name, address, tel and email'
    end
  end
  
  def self.delete_contact(name)
    Contact.delete_all("name = '#{name}'") 
  end                            
  
  def self.edit_contact(name, address, tel, email)
    c = Contact.find(:first, :conditions => "name='#{name}'")
    c.address = address unless address.nil?
    c.tel = tel unless tel.nil?
    c.email = email unless email.nil?
    c.save
  end
  
  def self.lookup_contact(name)
    Contact.find(:first, :conditions => "name = '#{name}'")
  end
  
  def self.dump_contacts
     Contact.find(:all)
  end
    
end

if __FILE__ == $0
  
  begin
    case ARGV[0]
      when 'add'
        Contact.add_contact(ARGV[1],ARGV[2], ARGV[3], ARGV[4])
      when 'delete'
        if(Contact.lookup_contact(ARGV[1]).nil?)
          puts 'Contact does not exist'
        else
          Contact.delete_contact(ARGV[1])
        end 
      when 'edit'
        if(ARGV[1].nil?)
          puts 'Specify contact name for editing'
        elsif(Contact.lookup_contact(ARGV[1]).nil?)
          puts 'Contact does not exist'
        else
          Contact.edit_contact(ARGV[1],ARGV[2], ARGV[3], ARGV[4])
        end 
      when 'lookup'
        puts Contact.lookup_contact(ARGV[1]).inspect
      when 'dump'
        Contact.dump_contacts.each {|c| puts c.inspect }
      else
        STDERR.puts 'Usage: contacts <add|delete|edit|lookup|dump> name address tel email' 
    end
  rescue Exception => error
     puts error
  end 
                         
end