Favorite是Deals和Preferences之间的联接表，该关联在rails控制台中正常运行。
[6] pry(main)> p = Preference.first
Preference Load (2.0ms) SELECT "preferences".* FROM "preferences" ORDER BY "preferences"."id" ASC LIMIT $1 [["LIMIT", 1]]
=> #<Preference:0x00007fb454b32f30
id: 1,
user_id: 2,
created_at: Thu, 31 Jan 2019 20:21:51 UTC +00:00,
updated_at: Thu, 31 Jan 2019 20:21:51 UTC +00:00>
[7] pry(main)> d = Deal.first
Deal Load (1.6ms) SELECT "deals".* FROM "deals" ORDER BY "deals"."id" ASC LIMIT $1 [["LIMIT", 1]]
=> #<Deal:0x00007fb453e05510
id: 1,
headline: "DCA to Des Moines, IA for $193 non-stop round trip - American Airlines",
description:
"This is a pretty great deal for a non-stop to DSM from DCA, but the departure dates are pretty limited from January 25 to February 25 (and not exactly daily but close). You can check out the calendar <a href='http://mail01.tinyletterapp.com/FaresYouCanUse/today-s-flights-iowa-new-hampshire-south-carolina-nevada/13473421-www.google.com/flights?c=cf040a38-8c96-4f9b-9338-8c223c053a53'>here</a>. After that, this route runs for more than $360 and sometimes more than $600! Though, prices are of course subject to change at any time, and I'm sure we'll see this fare fluctuate.",
start_date: Fri, 25 Jan 2019,
end_date: Mon, 25 Feb 2019,
created_at: Fri, 25 Jan 2019 19:42:51 UTC +00:00,
updated_at: Fri, 25 Jan 2019 20:28:12 UTC +00:00,
instructions: nil,
posted_date: Tue, 15 Jan 2019,
blog_head:
"I'm back on the grid - and bringing you a special 2020 Presidential Campaign Edition of Fares You Can Use.\n <br><br>\n I've been seeing some good deals for these particular locales for a while, and if you're planning some campaign travel (or to run for president), you may want to book these deals before the demand spike happens. \n <br><br>\n (I hope to provide an update on these for you every once in a while.)",
blog_foot: "",
region_id: 10,
slug: "dca-to-des-moines-ia-for-193-non-stop-round-trip-american-airlines">
[8] pry(main)> f = Favorite.new deal:d, preference:p
=> #<Favorite:0x00007fb45702fa18 id: nil, comment: nil, deal_id: 1, preference_id: 1, created_at: nil, updated_at: nil>
但是，在我的应用程序内部，当我尝试使用Favorite和Deal创建一个Preference时，出现了一个超现实的错误：
[3] pry(#<FavoritesController>)> f = Favorite.new(deal:d,preference:p)
ActiveRecord::AssociationTypeMismatch: Preference(#70244671627000) expected, got #<Preference id: 1, user_id: 2, created_at: "2019-01-31 20:21:51", updated_at: "2019-01-31 20:21:51"> which is an instance of Preference(#70244669337180)
我正在使用的对象在下面，因此您可以“检查我的工作”。
请忽略Preference和Preferences之间的任何混淆。我已经控制住了。
[1] pry(#<FavoritesController>)> d = Deal.find_by(slug: params[:deal_slug]
[1] pry(#<FavoritesController>)* )
Deal Load (0.8ms) SELECT "deals".* FROM "deals" WHERE "deals"."slug" = $1 LIMIT $2 [["slug", "iad-to-shanghai-for-403-round-trip-united-airlines"], ["LIMIT", 1]]
↳ (pry):8
=> #<Deal:0x00007fc63998eef8
id: 5,
headline: "IAD to Shanghai for $403 round trip - United Airlines",
description:
"This flight has one quick stop there and one quick stop on the way back, and is just about the best you can do for Shanghai. <i>And</i> all the flights in the route are operated by United, so you know exactly what you're getting! Lots of dates in February, March, and April. Find yours <a href='http://mail01.tinyletterapp.com/FaresYouCanUse/today-s-flights-shanghai-beijing-moscow-lisbon/13513653-www.google.com/flights?c=cf040a38-8c96-4f9b-9338-8c223c053a53'>here</a>. Make sure to check your flight times and who operates each flight before you book to confirm.",
start_date: Fri, 01 Feb 2019,
end_date: Tue, 30 Apr 2019,
created_at: Fri, 25 Jan 2019 19:42:51 UTC +00:00,
updated_at: Fri, 25 Jan 2019 20:28:12 UTC +00:00,
instructions: nil,
posted_date: Mon, 21 Jan 2019,
blog_head: nil,
blog_foot: nil,
region_id: 3,
slug: "iad-to-shanghai-for-403-round-trip-united-airlines">
[2] pry(#<FavoritesController>)> p = current_user.preferences
User Load (2.5ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 2], ["LIMIT", 1]]
↳ (pry):10
Preference Load (0.8ms) SELECT "preferences".* FROM "preferences" WHERE "preferences"."user_id" = $1 LIMIT $2 [["user_id", 2], ["LIMIT", 1]]
↳ (pry):10
=> #<Preference:0x00007fc6373d5720
id: 1,
user_id: 2,
created_at: Thu, 31 Jan 2019 20:21:51 UTC +00:00,
updated_at: Thu, 31 Jan 2019 20:21:51 UTC +00:00>
[3] pry(#<FavoritesController>)> f = Favorite.new(deal:d,preference:p)
ActiveRecord::AssociationTypeMismatch: Preference(#70244671627000) expected, got #<Preference id: 1, user_id: 2, created_at: "2019-01-31 20:21:51", updated_at: "2019-01-31 20:21:51"> which is an instance of Preference(#70244669337180)
from /Users/TuzsNewMacBook/.rvm/gems/ruby-2.3.7/gems/activerecord-5.2.2/lib/active_record/associations/association.rb:246:in `raise_on_type_mismatch!'