ruby-on-rails - 如何使用回调更新另一个模型？

Question

我正在使用一个名为 Recover 的模型。在创建模型之前，我想使用 Recover.combo_id 属性作为引用来保存 bool 属性 Combo.occupied = true。

看来我的 SQL 正在正确执行查询，但它没有保存此属性。如何保存 Combo.occupied = true？

恢复.rb:

before_create :checkin

protected

def checkin x = Combo.find_by_id(combo_id).occupied = true
end

Rails 控制台:

Started POST "/recovers" for 127.0.0.1 at 2011-01-06 17:07:24 -0800
Processing by RecoversController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"o1Iu3Y9/rVBOZPoDUgVP/tRfQ8GxbdWC40DbPq9YxUE=", "recover"=>{"combo_id"=>"4", "email"=>"jz@marin.edu"}, "commit"=>"Create Recover"} Recover Load (0.2ms) SELECT "recovers"."id" FROM "recovers" WHERE ("recovers"."email" = 'justin.zollars@marin.edu') LIMIT 1
Recover Load (0.1ms) SELECT "recovers"."id" FROM "recovers" WHERE ("recovers"."combo_id" = 4) LIMIT 1
Combo Load (0.5ms) SELECT "combos".* FROM "combos" WHERE ("combos"."id" = 4) LIMIT 1 AREL (0.5ms) INSERT INTO "recovers" ("locker_number", "email", "requests", "created_at", "updated_at", "combo_id") VALUES (NULL, 'justin.zollars@marin.edu', NULL, '2011-01-07 01:07:24.287072', '2011-01-07 01:07:24.287072', 4) Redirected to http://localhost:3000/recovers/14 Completed 302 Found in 119ms

RecoversController#创建

def create @recover = Recover.new(params[:recover])

respond_to do |format|
  if @recover.save
    format.html { redirect_to(@recover, :notice =>

'Recover was successfully created.') } format.xml { render :xml => @recover, :status => :created,

:location => @recover }

  else
    format.html { render :action => "new" }
    format.xml  { render :xml => @recover.errors, :status =>

:unprocessable_entity } end

end  

end

Answer 1

您需要调用 save 才能将新值写入数据库:

def checkin
  combo = Combo.find_by_id(combo_id)
  combo.occupied = true
  combo.save!
end

如果您使用 update_attribute，这会更容易。另外，如果你有 belongs_to 关系，你可以省去 find:

belongs_to :combo

def checkin
  if combo # true unless combo_id is nil
    combo.update_attribute(:occupied,true)
  end
end

请注意，update_attribute 会绕过验证。如果您需要验证，请改用 update_attributes(:occupied=>true)。