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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
我不太確定如何提出這個問題,因此我為這個笨拙的解釋表示歉意。
我有三個模型,用戶,用水量和目標
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
用水首先由用戶填寫,然后是目標。 目標是與用水用法完全相同的架構,但是使用了一部分用水用法形式並復制了用水用法中的其余屬性。
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
這是GoalsController
類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
我目前有以下錯誤:
NameError in GoalsController#create
undefined local variable or method `current_user' for #
<Goal:0x007fbedde9a590>
這似乎是我從用水模型中檢索信息的方式
self.household_size = @waterusage.household_size
有沒有我可以使用的聯接?
用水模型適用於BTW。
謝謝
不知道這是否是最好的方法,但是我會使用以下方法:
您可以使用after_initialize
回調來實現。 在您的目標模型中,
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,像這樣在執行Goal.new
,它將檢查該用戶的用水情況並在目標上初始化這些值。 因此,您不必在控制器上進行任何更改,即使您在控制台上進行了更改,它也可以正常工作。 猜猜這是使用模型回調來做的更好的做法。 不知道它是否可以解決您的問題,請嘗試一下。 祝好運!
您的錯誤消息是: NameError in GoalsController#create undefined local variable or method
: NameError in GoalsController#create undefined local variable or method
current_user'
current_user
對象由您使用的Devise gem在控制器內部自動定義。 它不會在模型中定義。
您的評論之一包括您在目標模型中使用的以下代碼段: current_user.waterusage.household_size
。 這就是您的錯誤消息所指的。 (請注意,您的其中一個評論摘錄與您原始帖子中的代碼不同。這使您更難確定這里出了什么問題。)
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