BP Study #15
ORマッパー対決〜２００８
Active Recordとか

自己紹介
• 尾崎 智仁
• ID:yuroyoro
• フリーエンジニア
• Java、最近はScala

Blog

ORマッパー
対決
ってことで

Active Record

ActiveRecordって?
•RailsでのO/R Mapper
•Railsなくてもつかえるけど
•ActiveRecordパターン
•Mapping定義が簡単
•class Member < ActiveRecord::Base

ActiveRecordって?
•DDL関係はMigrationで
•Act_as_*で振る舞いを拡張可能
•動的ファインダ
•Lazy Loading
•Named Scope ->イカス

やってみよう!

ActiveRecordを使う準備
•MySqlをインストールしておく
•MySqlにDatabaseを作っておく
•Railsアプリを生成する
•Migration書く

ActiveRecordを使う - 1
Railアプリを生成
$ rails ARTest
create
create app/controllers
create app/helpers
create app/models
create app/views/layouts
create config/environments
create config/initializers
create db
create doc

ActiveRecordを使う - 2
Modelを生成する
$ ./script/generate model member username:string password:string
¥ sex:decimal birthday:datetime last_login_time:timestamp
:0:Warning: Gem::SourceIndex#search support for Regexp patterns is deprecated
exists app/models/
exists test/unit/
exists test/fixtures/
create app/models/member.rb
create test/unit/member_test.rb
create test/fixtures/members.yml
create db/migrate
create db/migrate/20081127123415_create_members.rb

ActiveRecordを使う - 3
Migrateする
$ rake db:migrate
(in /Users/ozaki/dev/Project/sandbox/work/ARTest)
== 20081127123415 CreateMembers: migrating
====================================
-- create_table(:members)
-> 0.0049s
== 20081127123415 CreateMembers: migrated (0.0054s)
===========================

ActiveRecordを使う - 4
Consoleで確認
$ script/console
Loading development environment (Rails 2.1.0)
>> member=Member.find(:all)
=> []
>> Member.create
#<Member id: 1, username: nil, password: nil, first_name: nil,
last_name: nil, sex: nil, birthday: nil, last_login_time: nil,
created_at: \"2008-11-27 13:16:47\", updated_at: \"2008-11-27
13:16:47\">
>> Member.find(1)
=> #<Member id: 1, username: nil, password: nil, first_name: nil,
last_name: nil, sex: nil, birthday: nil, last_login_time: nil,
created_at: \"2008-11-27 13:16:47\", updated_at: \"2008-11-27
13:16:47”>

ActiveRecordを使う - 5
動的な属性ベースのファインダ
>> Member.find_by_username('Test2')
=> #<Member id: 2, username: \"Test2\", password: nil, first_name:
nil, last_name: nil, sex: nil, birthday: nil, last_login_time:
nil, created_at: \"2008-11-27 13:17:04\", updated_at: \"2008-11-
27 13:21:14\">

ActiveRecordを使う - 6
関連の設定
class Employee< ActiveRecord::Base
belongs_to :department
has_many :roles ,:through => :belongs
End
class Department< ActiveRecord::Base
has_many :employees
acts_as_tree :order => \"id\"
end

ActiveRecordを使う - 7
Named_scope
class Member < ActiveRecord::Base
named_scope :male,
:conditions=>[\"sex = ?\",1]
named_scope :recent,
lambda {|*args| {:conditions =>
[\"updated_at > ?\", args.first ||
1.day.ago]} }
end

ActiveRecord まとめ
よかったさがし
•Mapping定義は楽
•Pluginいっぱい
•Lazy Loading
•Irb上で簡単確認

ActiveRecord まとめ
Disってみる
Disってみる
•リファクタリング大変
•Migrationは計画的に
•IDEの補完が…
•Joinとかにがて

おまけ
Active Objects

ActiveObjectsって?
•ARパターンのJava実装
•Interfaceにgetter/setterで
•manager.migrate(Person.class);
•EntityManager
•アノテーション
•http://d.hatena.ne.jp/nattou_cur
ry_2/

ご清聴
ありがとう
ございました