Verweis in meiner Migration Fehler hinzufügen

Question

i Schienen neue demo_project erstellen mit MySQL-Datenbank mein Beglaubigungs ok war ich erstellen Tabelle meine mit rake db: create

Created database 'demo_project_development' 
Created database 'demo_project_test' 

dann erstelle ich einen Tisch

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

und es war Erfolg

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 

danach i erzeugen eine Migration

012.351.

rails g migration AddQtySoldToProducts qty_solid:integer 

und erstellen Sie diese

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

und danach mache ich eine weitere Migration

rails g migration AddRefNumToProducts ref_num:string:index 

und erstellen Sie diese

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

und die letzte Migration

rails g migration AddStyleToProducts style:references 

und schaffen diese

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

wenn ich rake db:migrate laufen bekam ich einen Fehler

== 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:in block 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: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: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: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: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: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: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: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: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: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: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:in add_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: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:in say_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:in change' /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: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: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:in with_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:in migrate' /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:in ddl_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: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:in each' /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:in block 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:in migrate' /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:in migrate' /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:in block (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:in eval' /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 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:in block 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: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: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: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: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: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: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: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: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: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: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:in add_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: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:in say_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:in change' /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: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: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:in with_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:in migrate' /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:in ddl_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: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:in each' /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:in block 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:in migrate' /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:in migrate' /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: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:in block 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: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: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: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: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: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: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: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: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: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: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:in add_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: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:in say_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:in change' /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: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: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:in with_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:in migrate' /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:in ddl_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: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:in each' /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:in block 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:in migrate' /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:in migrate' /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:in block (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:in eval' /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

Sie haben nicht eine styles Tisch.

Answer 2

Ja, bevor Sie diese Migration ausführen, sollten Sie Stil Tabelle anderen Weise erstellen Sie haben das gleiche Problem.

haben Sie einen Blick Link unten würde es Ihnen helfen könnte -

add_reference link1

add_reference link2

Hinweis: Wenn Sie irgendwo add_reference dann stellen Sie sicher, zuerst diese Tabelle vorhanden sein sollte, schreiben oder Wenn Sie zusammen alle Migrationen erstellen möchten, sollte die Reihenfolge der Migration zuerst die Migration der Referenztabellenerstellung nach dieser Migration sein, die add_reference hat.