如何以rails方式获取新创建记录的id？

假设我有 2 个模型model1 and model2. model1有很多model2. model2 belongs to model1. Save model1 and model2同时。

class Model1 < ActiveRecord::Base
  has_many :model2s
end

class Model2 < ActiveRecord::Base
  belongs_to :model1
end

def create
   @mod1 = Model1.new(model1_params)
   id = Model1.last.id + 1
   @mod2 = Model2.new(model1_id: id)
   if @mod1.save && @mod2.save 
    redirect root_path
   else
    render 'edit'
   end
end

在我删除 model1 的最后一条记录之前，该解决方案是可以的。如何获取 model1 创建之前的最后一条记录。

最符合规范的方法是这样的：

def create
  @mod1 = Model1.new(model1_params)
  @mod1.model2.build({args if you have them}) # this will only work if you have the relationship set up
  if @mod1.save
    # @mod1 is now saved along with model 2 who now has its ID
    # @mod1.id returns id, Model2.last returns model2 ID, Model2.last.model1_id returns Model1 ID
    #you can now delete model 1 if you wanted to, just make sure you don't have dependent destroy on in the model1.
    redirect root_path
  else
    render 'edit'
  end
end

希望能帮助到你！