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[英]Ruby on rails 3 - Join many models to update a field of one model using attributes from another model non related directly
[英]Rails: Setting Model Attributes to Attributes from Another Model
我不太确定如何提出这个问题,因此我为这个笨拙的解释表示歉意。
我有三个模型,用户,用水量和目标
class Goal < ApplicationRecord
belongs_to :user
end
class Waterusage < ApplicationRecord
belongs_to :user
end
class User < ApplicationRecord
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable,
has_one :waterusage, :dependent => :destroy
has_one :goals, :dependent => :destroy
end
用水首先由用户填写,然后是目标。 目标是与用水用法完全相同的架构,但是使用了一部分用水用法形式并复制了用水用法中的其余属性。
class Goal < ApplicationRecord
belongs_to :user
# before_validation :get_from_waterusage
before_validation :calculate_totals
def get_from_waterusage
self.household_size = @waterusage.household_size
self.swimming_pool = @waterusage.swimming_pool
self.bathroom_sink_flow_rate = @waterusage.bathroom_sink_flow_rate
self.low_flow_toilet = @waterusage.low_flow_toilet
self.kitchen_sink_usage = @waterusage.kitchen_sink_usage
self.kitchen_sink_flow_rate = @waterusage.kitchen_sink_flow_rate
self.dishwasher_rate = @waterusage.dishwasher_rate
self.dishwasher_multiplier = @waterusage.dishwasher_multiplier
self.laundry_rate = @waterusage.laundry_rate
self.laundry_multiplier = @waterusage.laundry_multiplier
self.lawn_size = @waterusage.lawn_size
self.carwash_rate = @waterusage.carwash_rate
self.carwash_multiplier = @waterusage.carwash_multiplier
self.miles = @waterusage.miles
self.statewater = @waterusage.statewater
self.percent_statewater = @waterusage.percent_statewater
self.pet_cost = @waterusage.pet_cost
end
...
end
这是GoalsController
类GoalsController <ApplicationController before_action:authenticate_user!
def new
@goal = goal.new
end
def create
#@user = User.find(params[:user_id])
@goal = current_user.create_goal(goal_params)
redirect_to goal_result_path
end
def destroy
@user = User.find(params[:user_id])
@goal = @user.goal.find(params[:id])
@goal.destroy
redirect_to user_path(current_user)
end
def show
@goal = goal.find(params[:id])
end
def results
if current_user.goal.get_individual_total > 6000
@temp = 6000
else
@temp = current_user.goal.get_individual_total
end
@goal = current_user.goal
end
private
def goal_params
params.require(:goal).permit(:household_size, :average_shower,
:shower_flow_rate, :bath_rate, :bath_multiplier,
:bathroom_sink_usage,
:bathroom_sink_flow_rate, :mellow, :low_flow_toilet,
:kitchen_sink_usage,
:kitchen_sink_flow_rate, :dishwasher_rate,
:dishwasher_multiplier,
:dishwasher_method, :laundry_rate, :laundry_multiplier,
:laundry_method,
:greywater, :lawn_rate, :lawn_multiplier, :lawn_size,
:xeriscaping,
:swimming_pool, :swimming_months, :carwash_rate,
:carwash_multiplier,
:carwash_method, :miles, :statewater, :percent_statewater,
:shopping,
:paper_recycling, :plastic_recycling, :can_recycling,
:textile_recycling,
:diet, :pet_cost, :individual_total, :household_total,
:home_usage, :outdoor_usage,
:individualDifference, :householdDifference, :vehicle_usage,
:power_usage, :indirect_source_usage,
:individualDifference, :householdDifference)
end
end
我目前有以下错误:
NameError in GoalsController#create
undefined local variable or method `current_user' for #
<Goal:0x007fbedde9a590>
这似乎是我从用水模型中检索信息的方式
self.household_size = @waterusage.household_size
有没有我可以使用的联接?
用水模型适用于BTW。
谢谢
不知道这是否是最好的方法,但是我会使用以下方法:
您可以使用after_initialize
回调来实现。 在您的目标模型中,
class Goal < ApplicationRecord
belongs_to :user
after_initialize :set_default_values
def set_default_values
waterusage = self.user.try(:waterusage)
if waterusage
self.attribute1 = waterusage.attribute1
self.attribute2 = waterusage.attribute2
self.attribute3 = waterusage.attribute3
#and it goes on...
end
end
end
因此,像这样在执行Goal.new
,它将检查该用户的用水情况并在目标上初始化这些值。 因此,您不必在控制器上进行任何更改,即使您在控制台上进行了更改,它也可以正常工作。 猜猜这是使用模型回调来做的更好的做法。 不知道它是否可以解决您的问题,请尝试一下。 祝好运!
您的错误消息是: NameError in GoalsController#create undefined local variable or method
: NameError in GoalsController#create undefined local variable or method
current_user'
current_user
对象由您使用的Devise gem在控制器内部自动定义。 它不会在模型中定义。
您的评论之一包括您在目标模型中使用的以下代码段: current_user.waterusage.household_size
。 这就是您的错误消息所指的。 (请注意,您的其中一个评论摘录与您原始帖子中的代码不同。这使您更难确定这里出了什么问题。)
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