Questions tagged «mysql2»

尝试mysql2为Rails 安装gem 时遇到一些问题。当我尝试通过运行安装它时，bundle install或者gem install mysql2出现以下错误： 安装mysql2时出错：错误：无法构建gem本机扩展。 如何解决此问题并成功安装mysql2？

485 mysql  ruby-on-rails  ruby  rubygems  mysql2 

在我的gemfile中，我有： gem 'mysql2' 我的database.yml如下： default: &default adapter: mysql2 database: <%= ENV['db_name'] %> username: <%= ENV['db_user'] %> password: <%= ENV['db_pass'] %> host: <%= ENV['db_host'] %> pool: 32 socket: <%= ENV['socket'] %> development: <<: *default production: <<: *default 我都运行了bundle update，bundle install并且我的Gemfile.lock显示mysql2。 但是，当我运行时，我rake db:migrate在计算机和登台服务器上都收到了此消息： myproject.com(master)$ rake db:migrate WARNING: Use strings for Figaro configuration. …

150 ruby-on-rails  ruby-on-rails-4  ruby-on-rails-4.1  mysql2  ruby-on-rails-4.2 

Gem::LoadError Specified 'mysql2' for database adapter, but the gem is not loaded. Add `gem 'mysql2'` to your Gemfile 加载以下文件时发生此错误： active_record/base 这是我在运行Rails服务器时遇到的错误。 The mysql2 gem has been added to the Gemfile as well. 我已经完成了bundle install，并尝试重新启动服务器，但仍然收到错误消息。

103 ruby-on-rails  mysql2  gemfile 

我正在尝试安装使用mysql2gem的开源Rails 3.2.21应用程序，但是当我尝试运行bundle命令时，出现以下错误： Fetching: mysql2-0.3.18.gem (100%) Building native extensions. This could take a while... p ERROR: Error installing mysql2: ERROR: Failed to build gem native extension. /Users/my_username/.rvm/rubies/ruby-2.1.2/bin/ruby -r ./siteconf20150614-72129-orqsb7.rb extconf.rb checking for ruby/thread.h... yes checking for rb_thread_call_without_gvl() in ruby/thread.h... yes checking for rb_thread_blocking_region()... yes checking for rb_wait_for_single_fd()... yes checking for rb_hash_dup()... …

84 mysql  ruby-on-rails  ruby  ruby-on-rails-4  mysql2 

我有3种型号： class Student < ActiveRecord::Base has_many :student_enrollments, dependent: :destroy has_many :courses, through: :student_enrollments end class Course < ActiveRecord::Base has_many :student_enrollments, dependent: :destroy has_many :students, through: :student_enrollments end class StudentEnrollment < ActiveRecord::Base belongs_to :student belongs_to :course end 我希望在“课程”表中查询课程列表，该列表在与某个学生相关联的“学生录取”表中不存在。 我发现也许使用Left Join是可行的方法，但似乎rails中的joins（）仅接受一个表作为参数。我认为可以执行的SQL查询是： SELECT * FROM Courses c LEFT JOIN StudentEnrollment se ON c.id …

80 sql  ruby-on-rails  ruby-on-rails-4  rails-activerecord  mysql2 

当我尝试安装mysql2 gem时，它失败，没有明显的错误。有谁知道该怎么做才能解决此问题，以便安装mysql2？ $ sudo gem install mysql2 Building native extensions. This could take a while... ERROR: Error installing mysql2: ERROR: Failed to build gem native extension. /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb checking for rb_thread_blocking_region()... no checking for mysql_query() in -lmysqlclient... no checking for main() in -lm... yes checking for mysql_query() in -lmysqlclient... no …

75 mysql  ruby  rubygems  mysql2  libmysql