我是Ruby on Rails的初学者,我使用的是Rails 3.0.9.
Gemfile和Gemfile.lockRails有什么区别？
我想使用ruby将.json文件转换为.csv文件.请帮我这样做.
还提出了实现这一目标的任何工具.
我想在日期上执行减法运算.
date_sent = Date.parse("2013-01-01") #=> Tue, 01 Jan 2013
date_now = Date.today #=> Wed, 04 Sep 2013
days = (date_now - date_sent) #=> (246/1)
为什么要date_now - date_sent退回Rational？
我正在尝试连接ROR应用程序中的多个数据库.我的database.yml在您的database.yml文件中看起来像这样
发展:
adapter: mysql
username: root
password:
database: example_development
私人的:
adapter: mysql
username: root
password:
database: example_private_development
可以使用establish_connection:private进行连接
我怀疑是如何使用rake db:create.我无法从谷歌获得解决方案.
请帮我清除它.
我正在使用 Rails-4，有一个产品模型和作为 JSon 类型存储的规范
在迁移文件中，添加
add_column :products, :specifications, :json
样品产品记录看起来像
#<Product id: 1, prod_id: 525141, cat_id: 6716, category_id: 5, updated: "2013-09-24 07:37:20", created_at: "2014-03-07 12:21:34", updated_at: "2014-03-07 12:32:36", eans: ["4016032274001"], skus: ["DK-1511-010F/WH"], account_id: 2, specifications: {"network"=>["PCI-Express 2.1 16x", "CardBus", "PCI-Express 3.0 16x", "PCI 64-bit, 66MHz", "PCI 64-bit, 33MHz", "PCI 32-bit, 66MHz", "PCI 3.0", "PCI 2.3", "PCI 2.2", "PCI-X", "PCI-Express 16x", "PCI-Express 8x", "PCI-Express 4x", "PCI-Express 2.0 16x", "PCI-Express 1x", "PCI", "PC Card", "ISA", "AGP 8x", "AGP 4x", "AGP 2x", "AGP …
当我执行"rake db:create"命令时,我得到了以下错误
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/version.rb:4: warning: already initialized constant MAJOR
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/version.rb:5: warning: already initialized constant MINOR
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/version.rb:6: warning: already initialized constant BUILD
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/version.rb:3: warning: already initialized constant NUMBERS
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/version.rb:9: warning: already initialized constant VERSION
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake.rb:26: warning: already initialized constant RAKEVERSION
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/early_time.rb:17: warning: already initialized constant EARLY
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/alt_system.rb:32: warning: already initialized constant WINDOWS
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/application.rb:28: warning: already initialized constant DEFAULT_RAKEFILES
WARNING: Possible conflict with Rake extension: String#ext already exists
WARNING: Possible conflict with Rake extension: String#pathmap already exists
/home/shamithc/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/task_arguments.rb:73: warning: already initialized constant EMPTY_TASK_ARGS …