postgresql - 创建表单（简单表单）的问题PG :: NotNullViolation：错误：Rails列中的空值

您好，当我尝试创建属于用户和Nounou的“孩子”时，我的应用程序Rails出现问题，但是我的问题是当我创建“孩子”时我是具有ID的用户，但是我没有还没有选择名词，所以我还没有名词ou_id，这是我的与众不同的代码（我尝试输入可选：true，但是不起作用：模型和模式

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