rake aborted! uninitialized constant Mysql2

Question

Goksel-Eryigits-Mac-mini:blog geryit$ rake db:migrate --trace
(in /Users/geryit/Sites/blog)
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** E         


        

Answer 1

Have you defined

gem 'mysql2'

in Gemfile? For Rails 3 and Bundler, it's not enough to install the gem, but to include it in Gemfile.

Answer 2

I was getting 'uninitialized constant Mysql' on Snow Leopard and Rails 3. Adding 'mysql' gem to Gemfile fixed it for me.

Answer 3

They work together now without any problems. The problem was Mysql version and mysql gem flags. I removed MYSQL 5.5 and installed Mysql 5.1 back. Everything is fixed. Thanks.

I wrote a blog post about installing, it can be helpful : https://geryit.com/blog/installing-mysql-with-rails-on-mac-os-x-snow-leopard/

Answer 4

Try uninstalling the mysql gem. It might be conflicting with the mysql2 gem you're using in your database.yml.