Please install mysql adapter 'gem install activerecord-mysql-adapter'

Question

I'm having trouble finding a solution to this problem. I'm getting the error:

Please install the mysql adapter: 'gem install activerecord-mysql-adapter'

 /Users/ Andy/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/rubygems_integration.rb:143:in `block in replace_gem': Please install the mysql adapter: `gem install activerecord-mysql-adapter` (mysql is not part of the bundle. Add it to Gemfile.) (LoadError)
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/connection_adapters/mysql_adapter.rb:5:in `<top (required)>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `block in require'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:48:in `resolve_hash_connection'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:39:in `resolve_string_connection'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:23:in `spec'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:127:in `establish_connection'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/railtie.rb:76:in `block (2 levels) in <class:Railtie>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/lazy_load_hooks.rb:26:in `on_load'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activerecord-3.2.1/lib/active_record/railtie.rb:74:in `block in <class:Railtie>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:30:in `instance_exec'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:30:in `run'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:55:in `block in run_initializers'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:54:in `each'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/initializable.rb:54:in `run_initializers'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/application.rb:136:in `initialize!'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /Users/ Andy /config/environment.rb:5:in `<top (required)>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `block in require'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/activesupport-3.2.1/lib/active_support/dependencies.rb:251:in `require'
    from /Users/ Andy /config.ru:4:in `block in <main>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
    from /Users/ Andy /config.ru:1:in `new'
    from /Users/ Andy /config.ru:1:in `<main>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `eval'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:40:in `parse_file'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:200:in `app'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/commands/server.rb:46:in `app'
    from /Users/ Andy/mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:301:in `wrapped_app'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/rack-1.4.1/lib/rack/server.rb:252:in `start'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/commands/server.rb:70:in `start'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:55:in `block in <top (required)>'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `tap'
    from /Users/ Andy /mysql2/ruby/1.9.1/gems/railties-3.2.1/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>' ```

Here is the gem env output.

  RubyGems Environment:
  - RUBYGEMS VERSION: 1.8.15
  - RUBY VERSION: 1.9.2 (2011-07-09 patchlevel 290) [x86_64-darwin11.2.0]
  - INSTALLATION DIRECTORY: /Users/ Andy/.rvm/gems/ruby-1.9.2-p290
  - RUBY EXECUTABLE: /Users/ Andy/.rvm/rubies/ruby-1.9.2-p290/bin/ruby
  - EXECUTABLE DIRECTORY: /Users/ Andy/.rvm/gems/ruby-1.9.2-p290/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-11
  - GEM PATHS:
     - /Users/ Andy/.rvm/gems/ruby-1.9.2-p290
     - /Users/ Andy/.rvm/gems/ruby-1.9.2-p290@global
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://rubygems.org/

If I can provide any more information please let me know.

Thanks, -Andy

---

Ps - My database.yaml already has mysql2 .

Answer 1

The problem is on your file config/database.yml

You should have a line that specify that the adapter is mysql2 (and not mysql)

adapter: mysql2

Instead of

adapter: mysql

Answer 2

对我有帮助的是在config / database.yml中指定适配器mysql2而不是mysql（注意数字！）。

Answer 3

1) You need to update your config/database.yml file and change:

adapter: mysql

into

adapter: mysql2

2) You need to update your Gemfile and explicitly add activerecord-mysql2-adapter dependency there:

gem 'mysql2'
gem 'activerecord-mysql2-adapter'

Answer 4

I never would have believed it but deleting my database.yml file and recreating it actually solved the problem for me too. Thanks Tyler. I spent hours installing and uninstalling different versions of the gems mysql, mysql2, activerecord-mysql-adapter, etc... In the end, my gemfile has

gem 'mysql2', "~>0.3.11"

and my database.yml file has

adapter: mysql2

I am on OSX 10.8, rails 3.2.8, and ruby 1.9.3.

By the way, I experienced the same issues with the mysql2 adapter on my Windows 7 machine. Uninstalling and even deleting the directory for the activerecord-mysql-adapter gem seemed to be critical as well.

Answer 5

This might be late but bundle install was installing 0.4.0 So I tried to edit the gem file and I replace mysql2 with

gem 'mysql2', "~>0.3.11"

and then

bundle install

in the terminal (This will install mysql2 0.3.11 and not the last version) I think active record have problems working with the last version. Well I hope it helps

Answer 6

You want to install the mysql2 gem .

Really, you should probably add it to your Gemfile :

gem "mysql2"

And then install your gems with bundler:

bundle install

Answer 7

Step 1. gem 'mysql2', "~>0.3.11" instead of gem 'mysql2' in Gemfile

Step 2. putting mysqllib.dll (available at mysql installation C:\\wamp\\bin\\mysql\\mysql5.5.24\\lib ) in the C:\\ruby2.0.0\\bin folder solved the rake db:migrate problem and successfully connected my rails with mysql ( database.yml contains mysql2)

I'm running windows 7, 64bit, mysql 64bit, ruby 2.0.0 [x64-mingw32]

Thanks you all for your inputs.

Answer 8

I had the same problem as OP on OSX Lion after upgrading to Rails 3.2. Removing all gems, bundle install, etc did not work. Gemfile and database.yml were correctly specifying mysql2.

In the end, I deleted and recreated my database.yml and everything works again. It was probably a typo or hidden character in the file.

Answer 9

If nothing helps (you have mysql2 as adapter in your database.yml ) and you are using RVM to manage your ruby versions, here is the simplest solution:

Try to remove all of your old gemsets (including global ), install a fresh ruby version and bundle again. I could solve the problem that way.

Answer 10

It is possible that you have changed adapter to mysql2 for a certain environment only but are not passing the environment to the rake command.

Eg I only changed mysql to mysql2 on the production environment but was running

rake generate_secret_token

when I changed it to the following it worked:

rake generate_secret_token RAILS_ENV=production

Answer 11

you have mentioned your database.yaml file already has mysql2 .

Its worth checking if you have activerecord-mysql2-adapter installed. (Note -mysql2- )

Answer 12

I would say that change the commented information on top in database.yml to

# 
# Install the MYSQL driver
#   gem install mysql2
#
# Ensure the MySQL gem is defined in your Gemfile
#   gem 'mysql2'
#
# And be sure to use new-style password hashing:
#   http://dev.mysql.com/doc/refman/5.0/en/old-client.html

second: add " gem 'mysql2' " (what ever is inside the double quotation marks) to gemfile .

save everything, do bundle install. Hope that helps.

or it just could be a typo.

Answer 13

I am facing the same issue and getting same error when run command

gem install activerecord-mysql2-adapter

you need to install libmysqlclient-dev

sudo apt-get install libmysqlclient-dev

It works for me

Answer 14

In my case, when I also got this error:

rake aborted! Please install the mysql adapter: gem install activerecord-mysql-adapter (mysql is not part of the bundle. Add it to Gemfile.)

After I searched Google and tried many ways, it didn't work. Finally, the answer is

• Navigate to the root of your app, run open gemfile
• Add the line gem 'mysql2', '< 0.3.7' directly below the gem line for rails.

Answer 15

For a old rails 2.3.18 ruby 1.8.7 app that I 'migrated' to a new MacBook (High Sierra - 10.13.6), in order to get the app to run (using POW) and to use script/console, I had to disable SIP and create a link to a file in /urs/lib/ directory. Migration Assistant was unable to create the link because of SIP.

To Disable SIP - System Integrity Protection

1. Boot into Mac OS Recovery Mode as usual by holding down the Command and R keys during system start.

2. Choose the language as usual (if applicable)

3. At the “MacOS Utilities” screen, pull down the “Utilities” menu from the top of the screen.

4. In terminal, type command: csrutil disable

5. Restart your computer

Finally, after restarting, in Terminal enter this command:

sudo ln /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib

Answer 16

I just added the following line to my Gemfile an it worked:

gem "mysql"

Before:

source 'https://rubygems.org'

gem "rails", "3.2.16"
gem "jquery-rails", "~> 2.0.2"
gem "coderay", "~> 1.1.0"
gem "fastercsv", "~> 1.5.0", :platforms => [:mri_18, :mingw_18, :jruby]
gem "builder", "3.0.0"
...

After:

source 'https://rubygems.org'

gem "mysql"
gem "rails", "3.2.16"
gem "jquery-rails", "~> 2.0.2"
gem "coderay", "~> 1.1.0"
gem "fastercsv", "~> 1.5.0", :platforms => [:mri_18, :mingw_18, :jruby]
gem "builder", "3.0.0"
...