Rails數據庫遷移無法添加外鍵

我試圖在我的rails項目中運行遷移時出現問題。Rails數據庫遷移無法添加外鍵

我有一個簡單的加法兩個表：

class ModifyCurrentTablesToNewDesign < ActiveRecord::Migration 
    def change 

    # Some other migrations... 

    # New Table Companies 

    create_table :companies do |t| 
     t.string :name 
    end 

    # New Table Teams 

    create_table :teams do |t| 
     t.string :name 
     t.belongs_to :companies, :index => true, :foreign_key => true 
    end 

    # Some oooother migrations... 

    end 
end

而當運行它，我有這樣的：

-- create_table(:companies) 
    -> 0.0036s 
-- create_table(:teams) 
rake aborted! 
StandardError: An error has occurred, this and all later migrations canceled: 

PG::UndefinedColumn: ERROR: column "company_id" referenced in foreign key constraint does not exist 
: ALTER TABLE "teams" ADD CONSTRAINT "fk_rails_e080df8a94" 
FOREIGN KEY ("company_id") 
    REFERENCES "companies" ("id") 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `block in execute' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract_adapter.rb:473:in `block in log' 
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.2.3/lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract_adapter.rb:467:in `log' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/postgresql/database_statements.rb:154:in `execute' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:762:in `add_foreign_key' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:217:in `block in create_table' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:216:in `each_pair' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/schema_statements.rb:216:in `create_table' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:661:in `block in method_missing' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:631:in `block in say_with_time' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:631:in `say_with_time' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:651:in `method_missing' 
/Users/julian/Development/sikuani/plataforma-eventos/db/migrate/20160121164754_modify_current_tables_to_new_design.rb:35:in `change' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:605:in `exec_migration' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:589:in `block (2 levels) in migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:588:in `block in migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:587:in `migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:764:in `migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:994:in `block in execute_migration_in_transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:1040:in `block in ddl_transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `block in transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/transaction.rb:184:in `within_new_transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/transactions.rb:220:in `transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:1040:in `ddl_transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:993:in `execute_migration_in_transaction' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:955:in `block in migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:951:in `each' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:951:in `migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:819:in `up' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/migration.rb:797:in `migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/tasks/database_tasks.rb:137:in `migrate' 
/Library/Ruby/Gems/2.0.0/gems/activerecord-4.2.3/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>' 
Tasks: TOP => db:migrate 
(See full trace by running task with --trace)

是不應該的是在創建表時companies ，默認情況下在內部創建了一列id？你能看到爲什麼會發生這種情況？

來源

2016-01-21 unmultimedio

看來你有一個1：M公司和團隊之間的關係。您需要使用單數，因爲一個團隊屬於單個公司，而不是多個公司。

t.belongs_to :company, :index => true, :foreign_key => true

來源

2016-01-21 17:46:09

它的工作！ ...但現在我很困惑：/，如果表被稱爲'公司'（複數），這種關係不在表名之間？ – unmultimedio

這樣想一下，一個團隊屬於**單個公司**，而不是多個公司。 –

Rails數據庫遷移無法添加外鍵

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