CODEWITHSUNDEEP
ruby-on-railsrubypostgresqlruby-on-rails-5
GeekFitness
GeekFitness

Reputation: 149

Rails5 - Adding Foreign Keys to Existing Models in postgres

I have two models. An Events model and an EventOption. The Events will have_many :event_options.

My issue is that when I try to do a migration to add_foreign key :event_options, :events so that I can link them up, I get the following error:

ActiveRecord::StatementInvalid: PG::UndefinedColumn: ERROR:  column "event_id" referenced in foreign key constraint does not exist
: ALTER TABLE "event_options" ADD CONSTRAINT "fk_rails_3995702fad"
FOREIGN KEY ("event_id")
  REFERENCES "events" ("id")

Here's my schema.rb:

ActiveRecord::Schema.define(version: 20160806001743) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "event_options", force: :cascade do |t|
    t.datetime "created_at",  null: false
    t.datetime "updated_at",  null: false
    t.float    "price"
    t.text     "description"
    t.string   "name"
  end

  create_table "events", force: :cascade do |t|
    t.datetime "created_at",                null: false
    t.datetime "updated_at",                null: false
    t.string   "name"
    t.boolean  "active",     default: true
  end

  create_table "users", force: :cascade do |t|
    t.datetime "created_at",                     null: false
    t.datetime "updated_at",                     null: false
    t.string   "email",                          null: false
    t.string   "encrypted_password", limit: 128, null: false
    t.string   "confirmation_token", limit: 128
    t.string   "remember_token",     limit: 128, null: false
    t.index ["email"], name: "index_users_on_email", using: :btree
    t.index ["remember_token"], name: "index_users_on_remember_token", using: :btree
  end

end

I know there are :id columns that work because I can play with them in the console. I know I'm missing something here to get the Foreign Keys working for the app, but for the life of me, I don't know what.

Upvotes: 0

Views: 2595

Answers (1)

j-dexx
j-dexx

Reputation: 10406

Wait, you mean the foreign key option for the has_many, that isn't what add_foreign_key does confusingly. It adds a foreign key constraint.

So in your migration you need to do add_column or add_reference first

add_reference :event_options, :event, index: true 
add_foreign_key :event_options, :events

Upvotes: 4

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