Переход с sqlite3 на mysql в существующем проекте

Question

Я добавил gem mysql2, как предлагалось в других решениях, а затем попытался создать модель, но я столкнулся с той же ошибкой.

Ниже приведен мой файл database.yml и сообщение об ошибке.Также обратите внимание, что я следую руководству, в котором мне нужно сначала сгенерировать модель, а затем запустить db: migrate.

default: &default
  adapter: mysql
  database: myrubyblog
  username: root
  password: root123
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

development:
  adapter: mysql
  database: myrubyblog
  username: root
  password: root123
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000
  # Warning: The database defined as "test" will be erased and
  # re-generated from your development database when you run "rake".
  # Do not set this db to the same as development or production.
test:
  adapter: mysql
  database: myrubyblog
  username: root
  password: root123
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

production:
  adapter: mysql
  database: myrubyblog
  username: root
  password: root123
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

---

sania@sania-Swift-SF314-52:~/myrubyblog$ rails g model category name:string
/home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require': Could not load 'active_record/connection_adapters/mysql_adapter'. Make sure that the adapter in config/database.yml is valid. If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add the necessary adapter gem to the Gemfile. (LoadError)
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `block in require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:258:in `load_dependency'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/connection_specification.rb:186:in `spec'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:880:in `establish_connection'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/connection_handling.rb:58:in `establish_connection'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/railtie.rb:124:in `block (2 levels) in <class:Railtie>'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:69:in `instance_eval'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:69:in `block in execute_hook'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:60:in `with_execution_control'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:65:in `execute_hook'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:50:in `block in run_load_hooks'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:49:in `each'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/lazy_load_hooks.rb:49:in `run_load_hooks'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/base.rb:326:in `<module:ActiveRecord>'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activerecord-5.1.6/lib/active_record/base.rb:25:in `<top (required)>'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `block in require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:258:in `load_dependency'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/activesupport-5.1.6/lib/active_support/dependencies.rb:292:in `require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:356:in `active_record_configured?'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:273:in `disconnect_database'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:107:in `preload'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:153:in `serve'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    from /home/sania/.rbenv/versions/2.5.0/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    from -e:1:in `<main>'

Answer 1

у вас неправильный адаптер базы данных, и у вашего файла проблема с отступами, попробуйте этот код

default: &default
  adapter: mysql2
  username: root
  password: root123
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  timeout: 5000

development:
  <<: *default
  database: myrubyblog_dev

test:
  <<: *default
  database: myrubyblog_test

production:
  <<: *default
  database: myrubyblog_prod

Answer 2

Вы можете решить эту проблему, выполнив следующий шаг:

1. gem 'mysql2' - добавьте этот камень в свой Gemfile

2. комплекта установкиИли обновление пакета

3. адаптер: mysql2 - Обновление вашего адаптера database.yml

Надеюсь, это поможет вам:)

Answer 3

В вашем файле config/database.yml должна быть строка, указывающая, что адаптер mysql2, а не mysql.

adapter: mysql2 вместо adapter: mysql

Если установка и комплектация mysql2 в порядке, она будет работать.

Возможно, вы захотите переустановить mysql2.Вы можете сделать это с помощью следующей команды

gem "mysql2"

bundle install