klochner

Join Table Columns (2.3ms)   SHOW FIELDS FROM `foos_bars`
  Resident Load (18.7ms)   SELECT * FROM `bars` INNER JOIN `foos_bars` ON `bars`.id = `foos_bars`.bar_id WHERE (`foos_bars`.foo_id = 1327 ) 
  SQL (0.1ms)   BEGIN
  SQL (51.2ms)   DELETE FROM `foos_bars` WHERE foo_id = 1327 AND bar_id in  (117261,117262,117263, . .

klochner

@foo.connection.execute("delete from foos_bars where foo_id = #{@foo.id}")}

klochner

class Foo < ActiveRecord::Base
  has_and_belongs_to_many :bars
end

class Bar < ActiveRecord::Base
  has_and_belongs_to_many :foos
end

@foo = Foo.create
@bars = Bar.find_all_by_some_attribute(:a)

klochner

Join Table Columns (2.3ms) SHOW FIELDS FROM `foos_bars`
  Bar Load (18.7ms) SELECT * FROM `bars` INNER JOIN `foos_bars` ON `bars`.id = `foos_bars`.bar_id WHERE (`foos_bars`.foo_id = 1327 )
  SQL (0.1ms) BEGIN
  SQL (51.2ms) DELETE FROM `foos_bars` WHERE foo_id = 1327 AND bar_id in (117261,117262,117263, . .

klochner

#try this data set:
ARR = [[1, "red"], [1, "green"], 
       [2, "red"], 
       [3, "yellow"], 
       [4, "red"], [4, "green"], [4, "yellow"], 
       [5, "green"], [5, "red"], 
       [6, "black"], 
       [7, "foo"], 
       [8, "bar"], 
       [9, "baz"], 

klochner

  FB.init({
    appId  : 'YOUR_APP_ID',
    status : true, // check login status
    cookie : true, // enable cookies to allow the server to access the session
    xfbml  : true  // parse XFBML
  });                           

  FB.getLoginStatus(function(response) {
    if (response.session) {
      // logged in and connected user, someone you know

klochner

def history(num=100)
  h = Readline::HISTORY.to_a
  start = [0,h.size-num-1].max
  h.zip((0..h.size).to_a)[start...h.size].each do |e,i| 
    puts " #{(i).to_s.rjust(4)}  #{e}"
  end;nil
end

>> history(7)
  483  def history(num=100)

klochner

#models/user.rb
def user_city
  read_attribute(:user_city) || address && address.city || ""
end

klochner

#models/user.rb
class User < ActiveRecord::Base
  has_one :address
  named_scope :with_city_info, 
              :joins=>:address, 
              :select="users.*, addresses.city as user_city"
end

#models/address.rb
class Address < ActiveRecord::Base

klochner

#models/user.rb
named_scope :with_city_info, 
            :joins=>:address, 
            :select="users.*, addresses.city as user_city"

#controllers/users_controller.b
def locations
  @users = User.with_city_info
end