So I'm learning more about belongs_to and has_many Associations in Rails and am combining it with ActiveAdmin.
I have created a Model "Semester" and a Model "Field". A Semester has many Fields and a Field belongs to Semester.
My field Class looks like this:
class Field < ApplicationRecord
belongs_to :semester
accepts_nested_attributes_for :semester, allow_destroy: true
end
and my Semester class looks like this:
class Semester < ApplicationRecord
has_many :fields
accepts_nested_attributes_for :fields, allow_destroy: true
end
Now I registered the Models with active admin with the following two files:
ActiveAdmin.register Field do
permit_params :name, semesters_attributes: [:name]
end
and
ActiveAdmin.register Semester do
permit_params :name, :fields, fields_attributes: [ :field_id, :name]
end
And now there are two issues that come up upon proceeding that I absolutely can not ged rid off:
1) If I do not add optional: true after belongs_to :semester I will get an error message "must exist" upon trying to create a new Field with a respective Semester.
2) If I do add optional: true after belongs_to :semester I will be able to create a new Field but the "Semester" will just be "EMPTY" in the new field.
The console output of case 2) will look like this:
Started POST "/admin/fields" for 127.0.0.1 at 2018-08-17 15:23:54 +0200
Processing by Admin::FieldsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"+GPjjNPOv9GsjXnEtEjBcC0xUMHKKC+YpFLfiUFUOgsgBJ+pLCucscrN0YaTk551GFp4K5lBEI2RW1clw2vCWw==", "field"=>{"semester_id"=>"2", "name"=>"MAVT"}, "commit"=>"Create Field"}
AdminUser Load (0.1ms) SELECT "admin_users".* FROM "admin_users" WHERE "admin_users"."id" = ? ORDER BY "admin_users"."id" ASC LIMIT ? [["id", 1], ["LIMIT", 1]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Unpermitted parameter: :semester_id
(0.0ms) begin transaction
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Field Create (0.6ms) INSERT INTO "fields" ("name", "created_at", "updated_at") VALUES (?, ?, ?) [["name", "MAVT"], ["created_at", "2018-08-17 13:23:54.026418"], ["updated_at", "2018-08-17 13:23:54.026418"]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
(12.2ms) commit transaction
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Redirected to http://0.0.0.0:3000/admin/fields/22
Completed 302 Found in 22ms (ActiveRecord: 13.0ms)
Started GET "/admin/fields/22" for 127.0.0.1 at 2018-08-17 15:23:54 +0200
Processing by Admin::FieldsController#show as HTML
Parameters: {"id"=>"22"}
AdminUser Load (0.2ms) SELECT "admin_users".* FROM "admin_users" WHERE "admin_users"."id" = ? ORDER BY "admin_users"."id" ASC LIMIT ? [["id", 1], ["LIMIT", 1]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Field Load (0.1ms) SELECT "fields".* FROM "fields" WHERE "fields"."id" = ? LIMIT ? [["id", 22], ["LIMIT", 1]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Rendering /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activeadmin-1.3.1/app/views/active_admin/resource/show.html.arb
(0.1ms) SELECT COUNT(*) FROM "active_admin_comments" WHERE "active_admin_comments"."resource_type" = ? AND "active_admin_comments"."resource_id" = ? AND "active_admin_comments"."namespace" = ? [["resource_type", "Field"], ["resource_id", 22], ["namespace", "admin"]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
ActiveAdmin::Comment Exists (0.1ms) SELECT 1 AS one FROM "active_admin_comments" WHERE "active_admin_comments"."resource_type" = ? AND "active_admin_comments"."resource_id" = ? AND "active_admin_comments"."namespace" = ? LIMIT ? OFFSET ? [["resource_type", "Field"], ["resource_id", 22], ["namespace", "admin"], ["LIMIT", 1], ["OFFSET", 0]]
↳ /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activerecord-5.2.1/lib/active_record/log_subscriber.rb:98
Rendered /home/divepit/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activeadmin-1.3.1/app/views/active_admin/resource/show.html.arb (73.4ms)
Completed 200 OK in 77ms (Views: 74.9ms | ActiveRecord: 0.5ms)
Thanks in advance for any tips on how to solve this! :)
First things first. Your associations are correct, but as per your associations you should not have field_id in semester table. Instead you should have semester_id in fields table. Also you should change semesters_attributes to semester_attributes
Unpermitted parameter: :semester_id
You should permit semester_id in the fields_attributes
fields_attributes: [ :semester_id, :name]
And finally in Rails 5, whenever a belongs_to association is defined, it is required to have the associated record present by default. To avoid this default behavior, you need to add optional: true