Question

我正在使用ruby（但不是rails）的活动记录。我正在使用sqlite3，它在文件上有一个test.db（不仅仅是在内存中）。当我使用user.create运行以下代码片段时，它会抱怨参数错误（当我使用use.save时，它会抛出一个活动记录异常。任何想法我可能做错了什么？谢谢

    require 'rubygems'
    gem 'activerecord'

    require 'sqlite3'
    require 'active_record'

    ActiveRecord::Base.logger = Logger.new(STDERR)
    #ActiveRecord::Base.colorize_logging = false

    ActiveRecord::Base.establish_connection(
      :adapter => 'sqlite3',
      :host => "localhost",
      :database => 'test.db'
    )

    class User < ActiveRecord::Base
        #attr_accessible :email, :full_name
      attr_accessor :email
      attr_accessor :full_name

    validates :email, presence: true, uniqueness: true

      def initialize(email, full_name)
        @email = email
        @full_name = full_name
      end
    end

    puts "full_name for user:"
    full_name = gets.chomp
    puts "email address:"
    email = gets.chomp
    user = User.new(email, full_name)
    #user.save
    user = User.create!(email: '', full_name: '')

第一种情况下的例外情况（使用User.create！）：

main.rb:42:in `initialize': wrong number of arguments (1 for 2) (ArgumentError)
        from /var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/inheritance.rb:61:in `new'
        from /var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/inheritance.rb:61:in `new'
        from /var/lib/gems/1.9.1/gems/activerecord-4.2.4/lib/active_record/persistence.rb:50:in `create!'
        from main.rb:55:in `<main>'

Answer 1

抱怨new方法。根据文档：（http://api.rubyonrails.org/classes/ActiveRecord/Base.html），您不需要initialize，因为当您从ActiveRecord::Base继承时，您需要使用哈希初始化您的对象。

user = User.new({email: email, full_name: full_name})
# or
user = User.new(email: email, full_name: full_name)
# then
user.save

您需要从代码中删除initialize和attr_accessor。

Answer 2

尝试评论User＃initialize方法并创建这样的新用户：

User.create! email: 'halk@mail.com', full_name: 'Halk'

<强>解释

当您根据ActiveRecord::Base课程的遗产声明AR模型时，您不需要定义自己的#initialize方法。但你做了。当您调用User::create!方法时，只传递一个参数 - Hash两对（使用email和full_name键）。但User#initialize分别定义两个参数 - email和full_name。所以Ruby异常提出并谈论它：

wrong number of arguments (1 for 2) (ArgumentError)

红宝石的活跃记录（不是铁轨）

2 个答案: