PG::UndefinedTable: ERROR: table "table-name" does not exist

Question

我正在弄乱我的数据库，创建和删除 tables。将它们推送到 heroku 后，我删除了一些迁移文件。之前我创建了一个table 'moms'。后来想重命名，就把'moms'删了，新建了table'minutes_of_meetings'。我做了 $rake db:migrate，一切都成功完成，我的应用程序运行在本地主机上完美运行。

将其推送到 heroku 后，当我执行 $heroku 运行 rake db:migrate 时，它生成了以下日志：

  ActiveRecord::SchemaMigration Load (0.7ms)  SELECT "schema_migrations".* FROM "schema_migrations"
  Migrating to DropMoms (20150823142852)
  (0.6ms)  BEGIN
             == 20150823142852 DropMoms: migrating =========================================
                 -- drop_table(:moms)
             (0.9ms)  DROP TABLE "moms"
             PG::UndefinedTable: ERROR:  table "moms" does not exist
             : DROP TABLE "moms"
             (0.5ms)  ROLLBACK
             rake aborted!
             StandardError: An error has occurred, this and all later migrations canceled:

                                                                                     PG::UndefinedTable: ERROR:  table "moms" does not exist
             : DROP TABLE "moms"/app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec'
      /app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `block in execute'

我在 heroku 中新建了一个 table 'moms' 以便在迁移运行时可以将其删除。我这样做了：

$ heroku run Ruby console for rails-app-name >> ActiveRecord::Migration.create_table :moms

我还创建了一个迁移来创建 table 'moms'。但错误仍然存在。

编辑：

这是我的 CreateMoms 迁移文件：

class CreateMoms < ActiveRecord::Migration
  def change
    create_table :moms do |t|
      t.string :name
      t.timestamp null: false
    end
  end
end

当我运行 heroku 运行 rake db:migrate:up

Running `rake db:migrate:up` attached to terminal... up, run.1729
rake aborted!
VERSION is required
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/databases.rake:78:in `block (3 levels) in <top (required)>'
Tasks: TOP => db:migrate:up
(See full trace by running task with --trace)
WARNING: Toolbelt v3.41.3 update available.

在 heroku 上运行 rake db:migrate:down

Running `rake db:migrate:down` attached to terminal... up, run.6389
rake aborted!
VERSION is required - To go down one migration, run db:rollback
/app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/databases.rake:86:in `block (3 levels) in <top (required)>'
Tasks: TOP => db:migrate:down
(See full trace by running task with --trace)
WARNING: Toolbelt v3.41.3 update available.

Answer 1

注意

rake db:schema:load 将从 heroku 数据库中清除所有数据。请确保您在 heroku 上有数据备份。如果您还没有 heroku 数据库的备份，您可以使用 Heroku PGBackups

轻松备份

看起来你的 schema 搞砸了。只需使用 rake db:schema:load 将模式加载到数据库，然后再次运行迁移：

heroku run rake db:schema:load
heroku run rake db:migrate

PG::UndefinedTable: ERROR: table "table-name" does not exist

PG::UndefinedTable: ERROR: table "table-name" does not exist

ruby

ruby-on-rails

heroku

rails-migrations

heroku-postgres

注意