用“航班”播撒数据库

Question

我正在尝试为我的数据库添加种子，我一直得到错误“ActiveRecord：：RecordIn有效值:验证失败:到达的航班必须存在”。在我在seeds.rb文件中创建关联的方法中，我提供了arrival_airport_id，所以我不知道问题出在哪里。

seeds.rb

Airport.delete_all
Flight.delete_all

#Airport seeds
airports = [
["Boston Logan International Airport", "BOS"],
["Gulfport", "GPT"],
["Jackson", "JAN"],
["Charleston", "CRW"]
]

airports.each do |full_name, name|
  Airport.create!( full_name: full_name, name: name )
end

  a = Airport.all[0..1]
  b = Airport.all[2..3]

  a.each_with_index do |a, index|
    a.departing_flights.create!(
      arrival_airport_id: b[index]
      )
  end

机场模式：

class Airport < ApplicationRecord
    has_many :departing_flights, class_name: "Flight", foreign_key: "departing_airport_id"
    has_many :arriving_flights, class_name: "Flight", foreign_key: "arrival_airport_id"
end

飞行模型：

class Flight < ApplicationRecord
    belongs_to :departing_flight, class_name: "Airport", foreign_key: "departing_airport_id"
    belongs_to :arriving_flight, class_name: "Airport", foreign_key: "arrival_airport_id" 
end

Answer 1

这是一个常见的错误，有两个解决办法。

a.each_with_index do |a, index|
  a.departing_flights.create!(
    arrival_airport_id: b[index]  # This line is the problem
    )
end

将对象分配给id列。可以将id分配给id列，也可以将对象分配给object列。

arrival_airport_id: b[index].id
# or
arrival_airport: b[index]

Rails会尽力帮助您，但是您必须给它正确的对象类型。