Problem with Creation form (Simpleform) PG::NotNullViolation: ERROR: null value in column with Rails

Question

Hello i have an issue with my app Rails when i try to create an "Enfant" who belongs to an user and a Nounou but my problem is when i create an "enfant" i'm a user with an ID but, I haven't chosen yet a nounou so i haven't got a nounou_id this is my differents code(i try to put optional: true but it doesn't work : Models and Schema

class Enfant < ApplicationRecord
  belongs_to :user
  belongs_to :nounou, optional: true
end


class Nounou < ApplicationRecord
  has_many :enfants
end


class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable
  has_many :enfants
end


  create_table "enfants", force: :cascade do |t|
    t.string "last_name"
    t.string "first_name"
    t.bigint "nounou_id", null: false
    t.bigint "user_id", null: false
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
    t.index ["nounou_id"], name: "index_enfants_on_nounou_id"
    t.index ["user_id"], name: "index_enfants_on_user_id"
  end

  create_table "nounous", force: :cascade do |t|
    t.string "name"
    t.integer "price"
    t.string "localisation"
    t.integer "evaluation"
    t.integer "places"
    t.string "first_name"
    t.string "last_name"
    t.string "photo"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
  end

  create_table "users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "encrypted_password", default: "", null: false
    t.string "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
    t.string "username"
    t.string "photo"
    t.string "first_name"
    t.string "last_name"
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end

end

Answer 1

There are two problems with the null: false option:

• It doesn't consider that the belongs_to association could be optional.
• If there are already records in the database, running the migration will generate an Exception, as there is not a default value (in PostgreSQL, PG::NotNullViolation: ERROR: column "user_id" contains null values).

Here's the reference.

Solution:

• Your form probably is sending nounou_id as nil or something. You need to verify that by inspecting your params reaching your create method.

• You have made nounou_id optional in model only but you need to run a migration to make it optional in db too where it clearly says it can't be false (null: false). You can take help for that migration from here.

• You should modify your enfant_params method in rails:

def enfant_params
  params.require(:enfant).permit(:last_name, :first_name, :user_id, :nounou_id)
end

I am confident that this will solve your issue but if you still need help, update your question with your form code, create action and enfant_params and updated schema.

Good Luck.