Type mismatch when seeding database - ruby-on-rails

Question

I'm trying to seed an application database, but I'm getting the following error:
ActiveRecord::AssociationTypeMismatch: Role(#97332160) expected,
got Fixnum(#76482890)
Here is the part of my schema.rb concerning the two table related to the problem:
create_table "roles", force: :cascade do |t|
t.string "role", limit: 50, null: false
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "users", force: :cascade do |t|
t.string "first_name", limit: 100, null: false
t.string "surname", limit: 100, null: false
t.string "email", limit: 255
t.integer "role_id", limit: 11
t.string "password", limit: 150
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_index "users", ["first_name"], name: "index_users_on_first_name", using: :btree
add_index "users", ["role_id"], name: "index_users_on_role_id", using: :btree
add_index "users", ["surname"], name: "index_users_on_surname", using: :btree
add_foreign_key "users", "roles"
And here are my seeds.rb commands:
rl = Role.create(role: "root")
User.create(first_name: "Edvaldo", surname: "Silva de Almeida Júnior", email: "edvaldo#my.domain.com", role_id: rl.id, password: "my_password")
rl = Role.create(role: "admin")
User.create(first_name: "Daiely", surname: "Fanchin", email: "daiely#my.domain.com", role_id: rl.id, password: "other_password")
rl = Role.create(role: "user")
User.create(first_name: "César", surname: "Silva", email: "cesar#my.domain.com", role_id: rl.id, password: "yet_other_password")
I found a question where the accepted answer suggested I should do something like:
rl = Role.create(role: "root")
User.create(first_name: "Edvaldo", surname: "Silva de Almeida Júnior", email: "edvaldo#my.domain.com", role_id: Role.find(rl.id), password: "my_password")
I tried that, but got the same error! Besides, I'm using the role_id as association, not the role itself. So, as far as I'm concerned, it should receive a Fixnum, not a Role.

Answer 1

add_foreign_key "users", "roles" this will add role_id column to users no required to separately write t.integer "role_id", limit: 11
there should be some associations
class User < ActiveRecord::Base
belongs_to :role
end
and
create_table "users", force: :cascade do |t|
t.string "first_name", limit: 100, null: false
t.string "surname", limit: 100, null: false
t.string "email", limit: 255
t.reference "role", index: true
t.string "password", limit: 150
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
add_foreign_key "users", "roles", column: :role_id
hope it might solve it.

Answer 2

I had added a method set_default_role to my User model.
class User < ActiveRecord::Base
has_one :role
after_initialize :set_default_role, :if => :new_record?
def set_default_role
if User.count == 0
self.role ||= 1
else
self.role ||= 2
end
end
end
But this method was wrong and as soon as I rewrote it as
def set_default_role
if User.count == 0
self.role_id ||= 1
else
self.role_id ||= 2
end
end
my seeding worked fine.
So, the problem was the fact I was tryind (inside this method) to set a Role to a Fixnum.
This serves as an advice to Rails newbies: Seeding is not just forcing something to your database. It is a full evaluation of your model and sometimes an error may be caused by the execution of some method, not just by the values you try to load.

Answer 3

The problem you have is simple:
role_id: Role.find(rl.id)
.find() returns a Role object.
Your create method is expecting a foreign_key (integer) (role_id: [int]).
The simple fix would be:
User.create(... role_id: Role.find(rl.id).id ...)
.. or ...
User.create(... role_id: rl.id ...)
... or even better ...
User.create(... role: rl ...)
--
Fix
The real fix would either to set a default in your database, or manually set the role_id, as you have in your submitted answer.
I would strong recommend using the database default because then it doesn't matter what happens in your app - your database will always "default" to the role you set:
$ rails g migration SetDefaultForRole
$ db/migrate/set_default_for_role_____.rb
class SetDefaultForRole < ActiveRecord::Migration
def change
change_column :users, :role_id, :integer, default: 0
end
end
$ rake db:migrate
The downside to this would be that this integer default would be set (unless you changed your db again). Whilst not a problem in itself, it would create an antipattern for your Role model (IE you can create any role, as long as it's after the initial one you made).
--
The other way would be to set the Role for the user.
You have this already; you could clean it up:
#app/models/user.rb
class User < ActiveRecord::Base
before_create :set_role, if: Proc.new { |m| m.role_id.blank? }
private
def set_role
self.role_id = "1" if User.count == 0
end
end