试图部署到heroku时出错（遵循ror教程）PG：：Error：Error：关系“users”的列“password_digest”已经存在

Question

因此，我关注http://www.railstutorial.org/book，evrything在本地运行良好（运行sqlight3)。

当我尝试时，我会得到以下错误

PG：：错误：错误：关系“users”的列“password_digest”已经存在：ALTER TABLE“users”添加列“password_digest”字符变化(255)/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:128:在中exec gems/activeRecord-4.0.8/lib/active_record/connection_adapters/abstract_adapter.rb:442:在log中的块中/app/vendor/bundle/ruby/2.0.0/gems/activeSupport-4.0.8/lib/active_support/notifications/instrumenter.rb:20:在tion_adapters/postgreSQL/database_statements.rb:127:在execute'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/connection_adapters/abstract/schema_statements.rb:360:在中add_column'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/connection_adapters/postgresql/schema_statements.rb:395:在中2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration。RB:601:在中的块在say_with_time'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration。RB:601:在中的say_with_time'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration。/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:575:inexec_migration'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:559:在块（2级）中的migrate'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:558:在块中的migrate:557:在中迁移'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration。RB:713:在中迁移'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration。RB:963:在中迁移'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord/migration。RB:1009:在ActiveRecord-4.0.8/lib/active_record/connection_adapters/abstract/database_statements.rb:203:intransact中的块ion'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/connection_adapters/abstract/database_statements.rb:211:inwithin_new_transaction'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/connection_adapters/abstratements.rb:203:intransaction 2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:1009:inDDL_transaction'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:962:inexecute_migration_in_transaction'/app/vendor/bundle/ruby/2.0.0/gems/active_record_in_transaction code>each'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:920:inmigrate'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:768:inup'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/migration.rb:746:inmigrate'/app/vendor/bundle/ruby/2.0.0/gems/activeRecord-4.0.8/lib/active_record/databases

我已经尝试过heroku PG：重置DATABASE_URL，然后重试。还尝试向.slugignore添加/spec、/lib、/script、/features、/cucumber.yml

这就是我的模式的样子：

ActiveRecord::Schema.define(version: 20140818041701) do

  create_table "users", force: true do |t|
    t.string   "name"
    t.string   "email"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.string   "password_digest"
    t.string   "remember_token"
    t.boolean  "admin",           default: false
  end

  add_index "users", ["email"], name: "index_users_on_email", unique: true
  add_index "users", ["remember_token"], name: "index_users_on_remember_token"

end

这就是我的密码摘要迁移的样子

class AddPasswordDigestToUsers < ActiveRecord::Migration
  def change
    add_column :users, :password_digest, :string
  end
end

Answer 1

您的表中已经有password_digest列，而使用迁移addpassworddigesttousers时，您正试图创建另一个列，这就是它创建问题的原因。删除迁移AddPasswordDigestTousers，并再次尝试运行rake db:migrate。Sqlite3在这种情况下不会产生任何错误。如果在迁移中编写intege而不是integer，则如果使用SQLite将不会产生任何错误。