如何使用rails4中的关联从excel上传数据

Question

我有三种模式，分别是经销商，城市和州，我在这里有经销商和城市之间的一对多关系。其次，有一个城市和国家之间的多对多关系：

class Dealer < ActiveRecord::Base 
    belongs_to :city 
end 

class City < ActiveRecord::Base 
    belongs_to :state 
    has_many :dealers 
end 

class State < ActiveRecord::Base 
    has_many :cities 
end 

在dealers_controller.rb我有一个方法：

def import 
    Dealer.import(params[:file]) 
    redirect_to dealers_path, notice: "Products imported." 
    end 

这将参考在经销商模式的方法：

def self.import(file) 
    spreadsheet = open_spreadsheet(file) 
    city = City.new 
    state = State.new 
    header = spreadsheet.row(1) 
    (2..spreadsheet.last_row).each do |i| 
     row = Hash[[header, spreadsheet.row(i)].transpose] 
     dealer = find_by_id(row["id"].to_i) || new 
     dealer.dealerName = row["DEALERSHIPNAME"] 
     dealer.address = row["ADDRESS"] 
     dealer.pincode = row["PINCODE"] 
     city.name = row["CITY"] 
     state.name = row["STATE"] 
     dealer.phoneNo = row["PHONENO"] 
     dealer.mobileNo = row["MOBILE"] 
     city.save! 
     state.save! 
     dealer.save! 
    end 
    end 

    def self.open_spreadsheet(file) 
    case File.extname(file.original_filename) 
    when '.xls' then Roo::Excel.new(file.path) 
    when '.xlsx' then Roo::Excelx.new(file.path) 
    else raise "Unknown file type: #{file.original_filename}" 
    end 
    end 

问题是，经销商数据完美地存储在经销商表中，但城市和州正在存储一次，只有最后一条记录，经销商表中的city_id为空，而且c_中的state_id ty表也是null。

如何使用此经销商模型上传城市和州表中的城市和州的全部数据？

我们如何上传Excel文件，它将填充所有三个表中的一对多关联？

Answer 1

i was creating the city and states object once outside of the loop but its instance must be created for every row which is coming from excel sheet, stores states unique and stores city according to states 


    def self.import(file) 
    spreadsheet = open_spreadsheet(file) 

    header = spreadsheet.row(1) 
    (2..spreadsheet.last_row).each do |i| 
     row = Hash[[header, spreadsheet.row(i)].transpose] 
     dealer = find_by_id(row["id"].to_i) || new 
     dealer.dealerName = row["DEALERSHIPNAME"] 
     dealer.address = row["ADDRESS"] 
     dealer.pincode = row["PINCODE"] 
     dealer.phoneNo = row["PHONENO"] 
     dealer.mobileNo = row["MOBILE"] 
     stateName = row["STATE"] 
     state = State.where(:name=>stateName).first 
     state_id = state.id unless state.nil? 
     name = row["CITY"] 
     city = City.where(:name=>name).first 
     city_id = city.id unless city.nil? 
     if state.nil? 
     stateObj = State.new 
     stateObj.name = stateName 
     stateObj.save! 
     if city.nil? 
     cityObj = City.new 
     cityObj.name = name 
     cityObj.state_id = stateObj.id 
     cityObj.save! 
     dealer.city_id = cityObj.id 
     dealer.save! 
     else 
     cityObj = City.new 
     cityObj.name = city.name 
     cityObj.state_id = stateObj.id 
     cityObj.save! 
     dealer.city_id = cityObj.id 
     dealer.save! 
     end 
     else 
     if city.nil? 
     cityObj = City.new 
     cityObj.name = name 
     cityObj.state_id = state.id 
     cityObj.save! 
     dealer.city_id = cityObj.id 
     dealer.save! 
     else 
     unless City.where(:name=>name).map{|c|c.state_id}.include? state.id 
     cityObj = City.new 
     cityObj.name = city.name 
     cityObj.state_id = state.id 
      cityObj.save! 
     dealer.city_id = cityObj.id 
     dealer.save! 
     else 
     dealer.city_id = City.where(:name=>name,:state_id =>state.id).first.id 
     dealer.save! 
     end 
     end 
     end 
    end 
    end 

    def self.open_spreadsheet(file) 
    case File.extname(file.original_filename) 
    when '.xls' then Roo::Excel.new(file.path) 
    when '.xlsx' then Roo::Excelx.new(file.path) 
    else raise "Unknown file type: #{file.original_filename}" 
    end 
    end