Rake Aborted,在add_index(:users,:email,{:unique => true})上

Question

我目前正在研究michael hartl的ruby on rails 3教程.当我尝试调用db:migrate时,我遇到了这个问题.有人可以帮我弄清楚为什么会流产.谢谢!

** Invoke db:migrate (first_time) ** Invoke environment (first_time) ** Execute environment ** Invoke db:load_config (first_time) ** Execute db:load_config ** Execute db:migrate == AddEmailUniquenessIndex: migrating ======================================== -- add_index(:users, :email, {:unique=>true}) rake aborted! An error has occurred, this and all later migrations canceled: SQLite3::ConstraintException: indexed columns are not unique: CREATE UNIQUE INDEX "index_users_on_email" ON "users" ("email")

码

class AddEmailUniquenessIndex < ActiveRecord::Migration
  def up
    add_index :users, :email, :unique => true
  end

  def down
    remove_index :users, :email
  end
end

用户代码

# == Schema Information
#
# Table name: users
#
#  id         :integer          not null, primary key
#  name       :string(255)
#  email      :string(255)
#  created_at :datetime         not null
#  updated_at :datetime         not null
#

class User < ActiveRecord::Base
  attr_accessor :password
  attr_accessible :email, :name, :password, :password_confirmation

  email_regex = /\A[\W+\-.]+@[a-z\d\-.]+\.|[a-z]+\z/i

  validates :name, :presence => true,
                   :length => { :maximum => 50 }
  validates :email, :presence => true,
                    :format => { :with => email_regex },
                    :uniqueness => { :case_sensitive => false }
  validates :password, :presence => true,
                       :confirmation => true,
                       :length => { :within => 6..40 }


end

Answer 1

您的迁移没有错.该错误仅表示您在db中存在电子邮件重复数据.

检查您的用户表,为现有行设置唯一的电子邮件或删除这些行.然后再次运行迁移.

更新:请注意,即使您从迁移中删除了唯一约束并添加validates_uniqueness_of :email到您的活动模型,该问题仍将在您将来吃掉.

根本问题是您的数据处于"不良"状态.如果你有两行具有相同的电子邮件地址(或者它也有可能他们都有空邮件),之后加入validates_uniqueness_of :email你的User模型实例,这两个行会是无效的.所以它仍然是你必须解决的数据问题.