Rake : db:schema:dump

Question

我正在使用Lynda.com服务器5.7、MySQL连接器C 6.1 6.1.2、Ruby1.9.3p392 (2013-02-22) i 386-mingw32和Rails 4.0.2通过Windows764上的MySQL完成Rails 3的基本培训。

在培训中，我在“数据库和迁移”一节中尝试将我在MySQL中创建的数据库与我的Rails项目同步，但是我遇到了一条中止消息。

讲师让我的班通过命令提示符打开rails项目并执行Rake来用以下代码构建一个"schema.rb“：

$ rake db:schema:dump

这条中止消息是每次输入该代码时的结果：

C:\Users\User\Documents\simple_cms>rake db:模式:转储 拉克流产了！ 不知道如何构建任务“db:schema:dump” (请参阅使用-- trace运行任务的完整跟踪)

在过去的24小时里，我花费了24小时的时间卸载、下载和重新安装多个版本的Rails，包括MySQL服务器和连接器，我花了最长的时间学习如何添加MySQL2 gem，这是我通过下载一个旧版本MySQL0.2.6完成的。

然而，尽管如此，这一中止的信息仍保持不变。

此外，当我键入rake -T时没有显示DB rakes，如下所示：

横扫 rake资产:清洁 rake资产:clobber rake资产:环境 rake资产:预编译 rake cache_digests:dependencies rake cache_digests:nested_dependencies

( db应该显示但不显示的地方)

rake doc:app ..。 rake测试:all:db ..。 rake tmp:创建

帮助？

请求的Gem文件

source '...'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.0.2'

# Use mysql as the database for Active Record
gem 'mysql2'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.0'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'

# See ... for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'

# Turbolinks makes following links in your web application faster. Read more: ...
gem 'turbolinks'

# Build JSON APIs with ease. Read more: ...
gem 'jbuilder', '~> 1.2'

group :doc do
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', require: false
end

# Use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.1.2'

# Use unicorn as the app server
# gem 'unicorn'

# Use Capistrano for deployment
# gem 'capistrano', group: :development

# Use debugger
# gem 'debugger', group: [:development, :test]

Answer 1

在database.yml文件中，您应该有如下内容：

default: &default
  adapter: mysql2
  encoding: utf8
  database: simple_cms_development
  pool: 5
  username: simple_cms
  password: secretpassword
  socket: /tmp/mysql.sock

development:
  <<: *default
  database: simple_cms_development

您可能应该检查database是否在实际环境(development)中正确定义。

注释:您没有任何带有db:命令的rake -T，所以问题在其他地方。

Answer 2

您将得到此错误。

~/Project$ rake db:schema:dump
rake aborted!
Don't know how to build task 'db:schema:dump'
(See full trace by running task with --trace)

因为rails应用程序中没有包含active_record

将以下行添加到application.rb

require "active_record/railtie"

现在试试，

~/Project$ rake -T

您应该能够看到rake db命令。

$ rails -T
rails about                              # List versions of all Rails frameworks and the environment
rails assets:clean[keep]                 # Remove old compiled assets
rails assets:clobber                     # Remove compiled assets
rails assets:environment                 # Load asset compile environment
rails assets:precompile                  # Compile all the assets named in config.assets.precompile
rails cache_digests:dependencies         # Lookup first-level dependencies for TEMPLATE (like messages/show or comments/_com...
rails cache_digests:nested_dependencies  # Lookup nested dependencies for TEMPLATE (like messages/show or comments/_comment....
rails db:create                          # Creates the database from DATABASE_URL or config/database.yml for the current RAI...
rails db:drop                            # Drops the database from DATABASE_URL or config/database.yml for the current RAILS...
rails db:environment:set                 # Set the environment value for the database
rails db:fixtures:load                   # Loads fixtures into the current environment's database
rails db:migrate                         # Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)
rails db:migrate:status                  # Display status of migrations
rails db:rollback                        # Rolls the schema back to the previous version (specify steps w/ STEP=n)
rails db:schema:cache:clear              # Clears a db/schema_cache.dump file
rails db:schema:cache:dump               # Creates a db/schema_cache.dump file
rails db:schema:dump                     # Creates a db/schema.rb file that is portable against any DB supported by Active R...
rails db:schema:load                     # Loads a schema.rb file into the database
rails db:seed                            # Loads the seed data from db/seeds.rb
rails db:setup                           # Creates the databa