ara's isolation

ara's isolation

a.rb

require 'rubygems'
require 'mysql'

loop do
#  Datum.transaction do

  connection = Mysql.new('localhost', 'root', 'password', 'ara_example')
  connection.autocommit false


  statement = connection.prepare("select value from data where id = 1")
  statement.execute
  a_value = statement.fetch.to_s

  statement = connection.prepare("select value from data where id = 2")
  statement.execute
  b_value = statement.fetch.to_s


  if a_value > b_value
    puts "a.value=0 / b.value=1"
#      Datum.a.update_attributes :value => 0
#      Datum.b.update_attributes :value => 1

    statement = connection.prepare("update data set value = 0 where id = 1")
    statement.execute

    statement = connection.prepare("update data set value = 1 where id = 2")
    statement.execute

  else
    puts "a.value=1 / b.value=0"
#      Datum.a.update_attributes :value => 1
#      Datum.b.update_attributes :value => 0

    statement = connection.prepare("update data set value = 1 where id = 1")
    statement.execute

    statement = connection.prepare("update data set value = 0 where id = 2")
    statement.execute
  end

  connection.commit
  connection.close

#  end
end

b.rb

require 'rubygems'
require 'mysql'

loop do
#  Datum.transaction do

  connection = Mysql.new('localhost', 'root', 'password', 'ara_example')
  connection.autocommit false


  statement = connection.prepare("select value from data where id = 1")
  statement.execute
  a_value = statement.fetch.to_s

  statement = connection.prepare("select value from data where id = 2")
  statement.execute
  b_value = statement.fetch.to_s

  if a_value > b_value
    puts "a.value=-1 / b.value=0"
#      Datum.a.update_attributes :value => -1
#      Datum.b.update_attributes :value => 0

    statement = connection.prepare("update data set value = -1 where id = 1")
    statement.execute

    statement = connection.prepare("update data set value = 0 where id = 2")
    statement.execute

  else
    puts "a.value=0 / b.value=-1"
#      Datum.a.update_attributes :value => 0
#      Datum.b.update_attributes :value => -1


    statement = connection.prepare("update data set value = 0 where id = 1")
    statement.execute

    statement = connection.prepare("update data set value = -1 where id = 2")
    statement.execute
  end

  connection.commit
  connection.close

#  end
end