Rails - 迁移混乱

Question

我希望有人可以帮我解决这个问题，而无需重新创建整个后端。

我正在使用 Rails，但在部署到 Heroku 时遇到了问题。我跑的时候

$ heroku run rake db:migrate

我的迁移失败，因为我的迁移删除了一个不存在的表。发生的事情是我有一个名为 Relations 的表，并将其重命名为 SchoolCityType (singular)。

删除表的迁移正在删除 SchoolCityTypes（复数，应该是）。

问题：我删除了迁移文件而不是回滚它，但 Heroku 仍然不会运行命令。

我该怎么办？提前致谢。

heroku 迁移错误信息：

== 20160407014126 DropSchoolDistrictCityTypesTable: migrating =================
-- drop_table(:school_district_city_types)
   (1.7ms)  DROP TABLE "school_district_city_types"
PG::UndefinedTable: ERROR:  table "school_district_city_types" does not exist
: DROP TABLE "school_district_city_types"
   (1.1ms)  ROLLBACK
rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:`== 20160407014126 DropSchoolDistrictCityTypesTable: migrating =================
-- drop_table(:school_district_city_types)
   (1.7ms)  DROP TABLE "school_district_city_types"
PG::UndefinedTable: ERROR:  table "school_district_city_types" does not exist
: DROP TABLE "school_district_city_types"
   (1.1ms)  ROLLBACK
rake aborted!
StandardError: An error has occurred, this and all later migrations canceled:

PG::UndefinedTable: ERROR:  table "school_district_city_types" does not exist
: DROP TABLE "school_district_city_types"
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `block in execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:473:in `block in log'
/app/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.2/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:467:in `log'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:154:in `execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/schema_statements.rb:116:in `drop_table'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:662:in `block in method_missing'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `block in say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:652:in `method_missing'
/app/db/migrate/20160407014126_drop_school_district_city_types_table.rb:3:in `change'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:606:in `exec_migration'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:590:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:589:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:588:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:765:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/transactions.rb:220:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:956:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `each'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:820:in `up'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:798:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
ActiveRecord::StatementInvalid: PG::UndefinedTable: ERROR:  table "school_district_city_types" does not exist
: DROP TABLE "school_district_city_types"
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `block in execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:473:in `block in log'
/app/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.2/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:467:in `log'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:154:in `execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/schema_statements.rb:116:in `drop_table'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:662:in `block in method_missing'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `block in say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:652:in `method_missing'
/app/db/migrate/20160407014126_drop_school_district_city_types_table.rb:3:in `change'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:606:in `exec_migration'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:590:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:589:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:588:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:765:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/transactions.rb:220:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:956:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `each'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:820:in `up'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:798:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
PG::UndefinedTable: ERROR:  table "school_district_city_types" does not exist
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `block in execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:473:in `block in log'
/app/vendor/bundle/ruby/2.3.0/gems/activesupport-4.2.2/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract_adapter.rb:467:in `log'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/database_statements.rb:154:in `execute'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/postgresql/schema_statements.rb:116:in `drop_table'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:662:in `block in method_missing'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `block in say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:632:in `say_with_time'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:652:in `method_missing'
/app/db/migrate/20160407014126_drop_school_district_city_types_table.rb:3:in `change'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:606:in `exec_migration'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:590:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:589:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:588:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:765:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:995:in `block in execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `block in ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/transaction.rb:188:in `within_new_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/transactions.rb:220:in `transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:1041:in `ddl_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:994:in `execute_migration_in_transaction'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:956:in `block in migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `each'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:952:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:820:in `up'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/migration.rb:798:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/tasks/database_tasks.rb:137:in `migrate'
/app/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.2/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate`

Answer 1

即使您删除了迁移，您仍然可以回滚。

我建议您回滚到您喜欢的位置，并从那里开始进行新的迁移。

希望对你有帮助

Answer 2

您似乎删除了创建“school_district_city_types”的迁移文件。您现在正试图删除以前不存在/创建的表。只需删除删除该表的迁移文件“20160407014126”即可。

Answer 3

您应该可以只删除迁移文件。以后像这样写你的迁移：

drop_table :school_district_city_types if (table_exists? :school_district_city_types)

你再也不会遇到这个问题了。