在我的迁移错误中添加引用

Question

我使用 mysql 数据库创建 rails 新 demo_project 我的凭据没问题我创建 table 我使用 rake db:create

Created database 'demo_project_development'
Created database 'demo_project_test'

然后我生成一个 table

rails g model Product name:string description:text inventory:integer 'price:decimal{7,2}' restocked_at:datetime

成功了

class CreateProducts < ActiveRecord::Migration[5.0]
  def change
    create_table :products do |t|
      t.string :name
      t.text :description
      t.integer :inventory
      t.decimal :price, precision: 7, scale: 2
      t.datetime :restocked_at

      t.timestamps
    end
  end
end

之后我生成迁移

rails g migration AddQtySoldToProducts qty_solid:integer

并创建这个

class AddQtySoldToProducts < ActiveRecord::Migration[5.0]
  def change
    add_column :products, :qty_solid, :integer
  end
end

然后我创建另一个迁移

rails g migration AddRefNumToProducts ref_num:string:index

并创建这个

class AddRefNumToProducts < ActiveRecord::Migration[5.0]
  def change
    add_column :products, :ref_num, :string
    add_index :products, :ref_num
  end
end

和最后一次迁移

rails g migration AddStyleToProducts style:references

并创建这个

class AddStyleToProducts < ActiveRecord::Migration[5.0]
  def change
    add_reference :products, :style, foreign_key: true
  end
end

当我运行 rake db:migrate 我得到一个错误

== 20170213061527 CreateProducts: migrating

-- create_table(:products) -> 0.1451s == 20170213061527 CreateProducts: migrated (0.1453s) ==========================

== 20170213061805 AddQtySoldToProducts: migrating ============================= -- add_column(:products, :qty_solid, :integer) -> 0.3441s == 20170213061805 AddQtySoldToProducts: migrated (0.3443s) ====================

== 20170213061950 AddRefNumToProducts: migrating ============================== -- add_column(:products, :ref_num, :string) -> 0.0964s -- add_index(:products, :ref_num) -> 0.4156s == 20170213061950 AddRefNumToProducts: migrated (0.5121s) =====================

== 20170213062130 AddStyleToProducts: migrating =============================== -- add_reference(:products, :style, {:foreign_key=>true}) rake aborted! StandardError: An error has occurred, all later migrations canceled:

Mysql2::Error: Cannot add foreign key constraint: ALTER TABLE products ADD CONSTRAINT fk_rails_326a064677 FOREIGN KEY (style_id) REFERENCES styles (id) /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:in _query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:inblock in query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:in handle_interrupt' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:inquery' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in block in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:589:inblock in log' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activesupport-5.0.1/lib/active_support/notifications/instrumenter.rb:21:in instrument' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:583:inlog' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/mysql/database_statements.rb:31:inexecute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:916:in add_foreign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:623:inforeign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:100:in add_to' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:826:inadd_reference' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:846:in block in method_missing' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:inblock in say_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:in say_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:835:inmethod_missing' /Users/cdasia-tsd/Desktop/demo_project/db/migrate/20170213062130_add_style_to_products.rb:3:in change' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:789:inexec_migration' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:773:in block (2 levels) in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:772:inblock in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in with_connection' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:771:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:951:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1212:inblock in execute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1282:in ddl_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1211:inexecute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1184:in block in migrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:ineach' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:in migrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:inblock in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1299:in with_advisory_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1006:in up' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:984:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/tasks/database_tasks.rb:161:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/railties/databases.rake:58:inblock (2 levels) in ' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/rake-12.0.0/exe/rake:27:in <top (required)>' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:ineval' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:in <main>' ActiveRecord::StatementInvalid: Mysql2::Error: Cannot add foreign key constraint: ALTER TABLEproductsADD CONSTRAINTfk_rails_326a064677FOREIGN KEY (style_id) REFERENCESstyles(id) /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:in_query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:in block in query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:inhandle_interrupt' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:in query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:inblock in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:589:in block in log' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activesupport-5.0.1/lib/active_support/notifications/instrumenter.rb:21:ininstrument' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:583:in log' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:inexecute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/mysql/database_statements.rb:31:in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:916:inadd_foreign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:623:in foreign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:100:inadd_to' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:826:in add_reference' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:846:inblock in method_missing' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:in block in say_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:insay_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:835:in method_missing' /Users/cdasia-tsd/Desktop/demo_project/db/migrate/20170213062130_add_style_to_products.rb:3:inchange' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:789:in exec_migration' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:773:inblock (2 levels) in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:772:in block in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:inwith_connection' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:771:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:951:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1212:in block in execute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1282:inddl_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1211:in execute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1184:inblock in migrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:in each' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:inmigrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:in block in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1299:inwith_advisory_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1006:inup' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:984:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/tasks/database_tasks.rb:161:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/railties/databases.rake:58:in block (2 levels) in <top (required)>' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/rake-12.0.0/exe/rake:27:in' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:in eval' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:in' Mysql2::Error: Cannot add foreign key constraint /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:in _query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:120:inblock in query' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:in handle_interrupt' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/mysql2-0.4.5/lib/mysql2/client.rb:119:inquery' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in block in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:589:inblock in log' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activesupport-5.0.1/lib/active_support/notifications/instrumenter.rb:21:in instrument' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_adapter.rb:583:inlog' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:218:in execute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/mysql/database_statements.rb:31:inexecute' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:916:in add_foreign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:623:inforeign_key' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_definitions.rb:100:in add_to' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:826:inadd_reference' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:846:in block in method_missing' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:inblock in say_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:815:in say_with_time' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:835:inmethod_missing' /Users/cdasia-tsd/Desktop/demo_project/db/migrate/20170213062130_add_style_to_products.rb:3:in change' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:789:inexec_migration' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:773:in block (2 levels) in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:772:inblock in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:398:in with_connection' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:771:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:951:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1212:inblock in execute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1282:in ddl_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1211:inexecute_migration_in_transaction' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1184:in block in migrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:ineach' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1183:in migrate_without_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:inblock in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1299:in with_advisory_lock' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1132:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:1006:in up' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/migration.rb:984:inmigrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/tasks/database_tasks.rb:161:in migrate' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/activerecord-5.0.1/lib/active_record/railties/databases.rake:58:inblock (2 levels) in ' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/gems/rake-12.0.0/exe/rake:27:in <top (required)>' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:ineval' /Users/cdasia-tsd/.rvm/gems/ruby-2.3.3/bin/ruby_executable_hooks:15:in `' Tasks: TOP => db:migrate (See full trace by running task with --trace) TSD-Interns-MacBook-Pro:demo_project cdasia-tsd$

Answer 1

您没有 styles table。

Answer 2

是的，在运行进行此迁移之前，您应该创建 style table 否则您会遇到同样的问题。

请看下面link可能对你有帮助-

add_reference link1

add_reference link2

注意：如果你在任何地方写 add_reference 那么请首先确保这个 table 应该存在，或者如果你想一起创建所有迁移那么迁移的顺序应该是参考的第一个迁移table 创作在那之后运行迁移其中有 add_reference。

在我的迁移错误中添加引用

Add reference in my migration error

ruby

activerecord

ruby-on-rails

ruby-on-rails-3

== 20170213061527 CreateProducts: migrating