（RubyonRails）帮助向DB添加哈希

Ruby 2.0、Rails 4.1.0、sQlite3。我必须在散列中创建参数以添加到我的数据库中。我有yaml文件和模型：

class User < ActiveRecord::Base
  has_many :tweets
  accepts_nested_attributes_for :tweets
end
class Tweet < ActiveRecord::Base
  belongs_to :user
end

并获取错误ActiveRecord:：UnknownAttributeError:未知属性：用户

---

怎么了？

首先，在Ruby中以大写字母开头的任何东西都被视为常量。 重新指定常数将导致警告。 具体而言：

UsTw_model_params = {user: []} # is a constant!

示例：

class User
module Huggable
TAU = 2 * PI

变量应为蛇形，例如：

user_tweet_params

其次，您可以将

for

循环留在后面。Ruby有更好的方法在数组和其他枚举中循环，比如

map

，

each

，等等

# Loop though seeds_yml["users"] and create a new array
user_tweet_params = seeds_yml["users"].map do |user|
    # with_indifferent_access allows us to use symbols or strings as keys
    user = user.with_indifferent_access
    user.slice!(:name, :email, :password, :avatar, :tweets)

    # Does the user have tweets?
    # We use try(:any?) incase user["tweets"] is nil
    if user[:tweets].try(:any?)
        # Take the tweets and nest then under tweet_attributes
        user[:tweet_attributes] = user.tweets.map do |tweet|
            tweet.with_indifferent_access.slice!(:post, :created_at)
        end
    end

    # remove the original tweets
    user.delete(:tweets)
    # return user
    user
end

---

有关详细信息，请参阅和。感谢您的详细回复

# Loop though seeds_yml["users"] and create a new array
user_tweet_params = seeds_yml["users"].map do |user|
    # with_indifferent_access allows us to use symbols or strings as keys
    user = user.with_indifferent_access
    user.slice!(:name, :email, :password, :avatar, :tweets)

    # Does the user have tweets?
    # We use try(:any?) incase user["tweets"] is nil
    if user[:tweets].try(:any?)
        # Take the tweets and nest then under tweet_attributes
        user[:tweet_attributes] = user.tweets.map do |tweet|
            tweet.with_indifferent_access.slice!(:post, :created_at)
        end
    end

    # remove the original tweets
    user.delete(:tweets)
    # return user
    user
end