如何使用Faker Gem填充属于模型

Question

当前模式是这样的：

ActiveRecord::Schema.define(version: 20160622075955) do
  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"
  create_table "posts", force: :cascade do |t|
    t.string   "title"
    t.string   "body"
    t.date     "date"
    t.integer  "user_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end
  add_index "posts", ["user_id"], name: "index_posts_on_user_id", using: :btree
  create_table "users", force: :cascade do |t|
    t.string   "first_name"
    t.string   "last_name"
    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", ["last_name"], name: "index_users_on_last_name", using: :btree
  add_foreign_key "posts", "users"
end

试图填充这两个模型：帖子＆amp;用户

这就是我对seeds.rb

20.times do |n| 
    a = User.new
    a.first_name = Faker::Name.first_name
    a.last_name = Faker::Name.last_name
    a.save
end
10.times do |n|
    b = Post.new
    b.title = Faker::Book.title
    b.body = Faker::Lorem.words(4, true)
    b.date = Faker::Time.between(DateTime.now - 1, DateTime.now) 
    b.save
end

它适用于User，但不适合Post。我还如何填充Post？

编辑

POST的模型

class Post < ActiveRecord::Base
  belongs_to :user
  validates :title, :body, presence: true
  validates :title, length: { maximum: 40 }
end

用户的模型

class User < ActiveRecord::Base
    has_many :posts
    validates :first_name, :last_name, presence: true
end

用户的控制器

class UsersController < ApplicationController
  def index
    @users = User.all
  end
  def show
    @user = User.find(params[:id])
  end
  def new
    @user = User.new
  end
  def create
    @user = User.new(user_params)
    if @user.save 
      flash[:notice] = "User successfully added!"
      redirect_to users_path
    else
      render :new
    end
  end
  def edit
    @user = User.find(params[:id])
    render :edit
  end
  def update
    @user = User.find(params[:id])
    if @user.update(user_params)
      redirect_to users_path
    else
      render :edit
    end
  end
  def destroy
    @user = User.find(params[:id])
    @user.destroy
      redirect_to users_path
  end
  private 
    def user_params
      params.require(:user).permit(:first_name, :last_name)
    end
end

POST的控制器

class PostsController < ApplicationController
  def new 
    @user = User.find(params[:user_id])
    @post = @user.posts.new
  end
  def edit
    @user = User.find(params[:user_id])
    @post = @user.posts.find(params[:id])
    render :edit
  end
  def create 
    @user = User.find(params[:user_id])
    @post = @user.posts.new(post_params)
    if @post.save 
      redirect_to user_path(@post.user)
    else
      render :new
    end
  end
  def update 
    @user = User.find(params[:user_id])
    @post = @user.posts.find(params[:id])
    if @post.update(post_params)
      redirect_to user_path(@post.user)
    else
      render 'edit'
    end
  end

  def destroy
    @user = User.find(params[:user_id])
    @post = @user.posts.find(params[:id])
    @post.destroy
      redirect_to users_path
    end
  private 
  private 
    def post_params
      params.require(:post).permit(:title, :body, :date)
    end
end

编辑两个

当我将puts b.errors.inspect放入seeds.rb文件中时，没有错误出现。

但是，当我运行rake db:seed

时，这就是显示在终端中的原因

#<ActiveModel::Errors:0x007fa20d45aec8 @base=#<Post id: 1, title: "Surprised by Joy", body: "["sunt", "audentia", "pectus", "omnis"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d463a28 @base=#<Post id: 2, title: "The Golden Bowl", body: "["cohibeo", "verus", "ut", "corrupti"]", date: "2016-06-27", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d450220 @base=#<Post id: 3, title: "Such, Such Were the Joys", body: "["video", "tepesco", "stabilis", "esse"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d439d18 @base=#<Post id: 4, title: "Jesting Pilate", body: "["aut", "textor", "tui", "subiungo"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d428888 @base=#<Post id: 5, title: "Great Work of Time", body: "["cupiditas", "debeo", "decipio", "clementia"]", date: "2016-06-27", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d4192c0 @base=#<Post id: 6, title: "Look to Windward", body: "["totidem", "numquam", "ut", "amita"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d409d70 @base=#<Post id: 7, title: "Vile Bodies", body: "["cruentus", "adiuvo", "stella", "cimentarius"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d3fa6e0 @base=#<Post id: 8, title: "Consider the Lilies", body: "["dolor", "sumptus", "solutio", "theologus"]", date: "2016-06-27", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d3eaf38 @base=#<Post id: 9, title: "Terrible Swift Sword", body: "["aspernatur", "aegrus", "studio", "adstringo"]", date: "2016-06-26", user_id: nil, created_at: "2016-06-28 04:38:02", updated_at: "2016-06-28 04:38:02">, @messages={}>
#<ActiveModel::Errors:0x007fa20d3db920 @base=#<Post id: nil, title: "By Grand Central Station I Sat Down and Wept", body: "["earum", "rerum", "defessus", "sed"]", date: "2016-06-26", user_id: nil, created_at: nil, updated_at: nil>, @messages={:title=>["is too long (maximum is 40 characters)"]}>

Answer 1

错误是Faker在某些时候创建大于40个字符的标题。（请看，在上面的示例中，您创建了9个帖子（因为它们具有ID），并且只有一个失败（最后一个错误消息）

@messages = {：title => ["太长（最大为40个字符）"]}

如果您想使用伪造者，则可以删除标题。

b.title = Faker::Book.title[0..40] 
# it will get only the first 40 characters

这样，您将为每个帖子创建20个用户。您可以再添加5.Times DO ...结束帖子创建，以便为每个用户提供5个帖子。您还可以仅创建一个用户，然后设置所有post.user = user.first，因此您将拥有一个带有很多帖子的用户。

20.times do
    user = User.new
    user.first_name = Faker::Name.first_name
    user.last_name = Faker::Name.last_name
    user.save
    post = Post.new
    post.title = Faker::Book.title[0..40]
    post.body = Faker::Lorem.words(4, true)
    post.date = Faker::Time.between(DateTime.now - 1, DateTime.now) 
    post.user = user
    post.save
end