Add reference in my migration error

Question

i create rails new demo_project using using mysql database my credentials was ok i create table my using rake db:create

Created database 'demo_project_development'
Created database 'demo_project_test'

then i generate a table

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

and it was success

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

after that i generate a migration

rails g migration AddQtySoldToProducts qty_solid:integer

and create this

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

and after that i create another migration

rails g migration AddRefNumToProducts ref_num:string:index

and create this

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

and the last migration

rails g migration AddStyleToProducts style:references

and create this

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

when i run rake db:migrate i got an error

== 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: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: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 TABLEproductsADD CONSTRAINT fk_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: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: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: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

You don't have a styles table.

Answer 2

Yes, before running this migration you should create style table other wise you got same issue.

Please have a look below link might be it would help you -

add_reference link1

add_reference link2

Note: if you are writing anywhere add_reference then please make sure first this table should be present or if you want to create together all migration then order of migration should be first migration of reference table creation after that run migration which have add_reference.