blog$ rails g model post title:string content:text
      invoke  active_record
      create    db/migrate/20120505085607_create_posts.rb
      create    app/models/post.rb
      invoke    test_unit
      create      test/unit/post_test.rb
      create      test/fixtures/posts.yml

blog$ rake db:migrate
==  CreatePosts: migrating ====================================================
-- create_table(:posts)
   -> 0.0009s
==  CreatePosts: migrated (0.0011s) ===========================================

blog$ rails c
Loading development environment (Rails 3.2.3)
irb(main):001:0> post = Post.new(:title => "Fisrt Post", :content=>"Content for first post")
=> #<Post id: nil, title: "Fisrt Post", content: "Content for first post", created_at: nil, updated_at: nil>

irb(main):002:0> post.save
   (0.1ms)  begin transaction
  SQL (47.9ms)  INSERT INTO "posts" ("content", "created_at", "title", "updated_at") VALUES (?, ?, ?, ?)  [["content", "Content for first post"], ["created_at", Sat, 05 May 2012 09:09:01 UTC +00:00], ["title", "Fisrt Post"], ["updated_at", Sat, 05 May 2012 09:09:01 UTC +00:00]]
   (8.1ms)  commit transaction
=> true

irb(main):003:0> post
=> #<Post id: 1, title: "Fisrt Post", content: "Content for first post", created_at: "2012-05-05 09:09:01", updated_at: "2012-05-05 09:09:01">

irb(main):004:0> Post.create(:title => "Second Post", :content => "Content for second post")
   (0.1ms)  begin transaction
  SQL (0.4ms)  INSERT INTO "posts" ("content", "created_at", "title", "updated_at") VALUES (?, ?, ?, ?)  [["content", "Content for second post"], ["created_at", Sat, 05 May 2012 09:11:09 UTC +00:00], ["title", "Second Post"], ["updated_at", Sat, 05 May 2012 09:11:09 UTC +00:00]]
   (7.7ms)  commit transaction
=> #<Post id: 2, title: "Second Post", content: "Content for second post", created_at: "2012-05-05 09:11:09", updated_at: "2012-05-05 09:11:09">

irb(main):005:0> posts = Post.all
  Post Load (0.2ms)  SELECT "posts".* FROM "posts"
=> [#<Post id: 1, title: "Fisrt Post", content: "Content for first post", created_at: "2012-05-05 09:09:01", updated_at: "2012-05-05 09:09:01">, #<Post id: 2, title: "Second Post", content: "Content for second post", created_at: "2012-05-05 09:11:09", updated_at: "2012-05-05 09:11:09">]

irb(main):006:0> post = Post.find(2)
  Post Load (0.3ms)  SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT 1  [["id", 2]]
=> #<Post id: 2, title: "Second Post", content: "Content for second post", created_at: "2012-05-05 09:11:09", updated_at: "2012-05-05 09:11:09">

irb(main):007:0> post.title
=> "Second Post"

irb(main):008:0> post.content
=> "Content for second post"

irb(main):009:0> post.title = "Our 2nd Post"
=> "Our 2nd Post"

irb(main):010:0> post.save
   (0.1ms)  begin transaction
   (0.2ms)  UPDATE "posts" SET "title" = 'Our 2nd Post', "updated_at" = '2012-05-05 09:12:58.570208' WHERE "posts"."id" = 2
   (8.7ms)  commit transaction
=> true

irb(main):011:0> post.update_attribute(:content, "Content for our 2nd post")
   (0.1ms)  begin transaction
   (0.2ms)  UPDATE "posts" SET "content" = 'Content for our 2nd post', "updated_at" = '2012-05-05 09:14:20.311204' WHERE "posts"."id" = 2
   (7.5ms)  commit transaction
=> true

irb(main):013:0> post.update_attributes(:title => "Second Post", :content => "Content for second post")
   (0.1ms)  begin transaction
   (0.3ms)  UPDATE "posts" SET "title" = 'Second Post', "content" = 'Content for second post', "updated_at" = '2012-05-05 09:16:53.926752' WHERE "posts"."id" = 2
   (7.9ms)  commit transaction
=> true

irb(main):014:0> post
=> #<Post id: 2, title: "Second Post", content: "Content for second post", created_at: "2012-05-05 09:11:09", updated_at: "2012-05-05 09:16:53">

irb(main):015:0> post.destroy
   (0.1ms)  begin transaction
  SQL (0.5ms)  DELETE FROM "posts" WHERE "posts"."id" = ?  [["id", 2]]
   (7.8ms)  commit transaction
=> #<Post id: 2, title: "Second Post", content: "Content for second post", created_at: "2012-05-05 09:11:09", updated_at: "2012-05-05 09:16:53">

irb(main):016:0> Post.find(2)
  Post Load (0.1ms)  SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT 1  [["id", 2]]
ActiveRecord::RecordNotFound: Couldn't find Post with id=2
    from /usr/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_record/relation/finder_methods.rb:340:in `find_one'
    from /usr/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_record/relation/finder_methods.rb:311:in `find_with_ids'
    from /usr/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_record/relation/finder_methods.rb:107:in `find'
    from /usr/lib/ruby/gems/1.9.1/gems/activerecord-3.2.3/lib/active_record/querying.rb:5:in `find'
    from (irb):16
    from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/commands/console.rb:47:in `start'
    from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/commands/console.rb:8:in `start'
    from /usr/lib/ruby/gems/1.9.1/gems/railties-3.2.3/lib/rails/commands.rb:41:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'