ruby-on-rails-3

问题 I have a working SQL query thanks to the help of Erwin Brandstetter in my earlier question 'Order with a has_many relationship'. How would I turn this SQL into an ActiveRecords or AREL query for use in a scope? SELECT a.* FROM articles a LEFT JOIN ( SELECT DISTINCT ON (article_id) article_id, value FROM metrics m WHERE name = 'score' ORDER BY article_id, date_created DESC ) m ON m.article_id = a.id ORDER BY m.value DESC; The closest I have come is with a friends help... scope :highest_score,

问题 I'm adding quiz functionality to the twitter app from the Hartl tutorial and have these Models: User is nearly the same as the tutorial: class User < ActiveRecord::Base has_many :followed_users, through: :relationships, source: :followed has_many :takens, dependent: :destroy has_many :questions, through: :takens end Taken is a table of Question ids to User ids: class Taken < ActiveRecord::Base belongs_to :user belongs_to :question end nothing interesting in Question: class Question <

问题 I have an image of a map.png file on part of a page. I would like this image to be clickable, and then to download the pdf version of that image. I've been using this as a reference Rails 3.1, can't make link_to image_path?, but I'm not sure how to proceed. It looks like I also need to edit something with the way the page is routed. Thanks for all the help! 回答1: Do you have a route to the pdf download or is the file itself a static asset? You can use a standard link_to helper with an image

问题 I want to generate an option tag like this: <option name="option_1" value="1">Small</option> <option name="option_2" value="2">Medium</option> Using my call like this: <%= select_tag option.name, options_from_collection_for_select(option.option_values, "id", "name"), include_blank: true %> Gets me half-way there, by generating this: <option value="1">Small</option> <option value="2">Medium</option> How do I add the name attribute to the option tag, using this structure? Is that even possible?

问题 The log out link in my app has been working fine, then it just stopped working. I haven't tested it for a while, but I haven't made any changes to anything related to it for a month! It is sending a GET request when it should be interpreted by the controller as a DELETE request. Here is my code: My ERB file in my view includes this line: <li><%= link_to('Log Out', destroy_user_session_path, :method => :delete)%></li> and also includes this: <%= javascript_include_tag "application" %> This is

问题 I have these tables and relationships: user has_many projects project has_many tasks task has_many actions I would like to build a scope that allows me to select all of the current users actions, regardless of what project or task they belong to. Thanks 回答1: I don't think scopes are necessary for this if you use the nested_has_many_through plugin. class User < ActiveRecord::Base has_many :projects has_many :tasks, :through => :projects has_many :actions, :through => :tasks end class Project <

问题 I just discovered that there isnt a default directory assets/images when I generate a Rails 4 app (Rails 4 rc1 currently). Whereas in Rails 3.1/3.2 its generated. Please tell me why is that so? I mean I can create a directory in a second, but thats not the point. If I didnt get the reason for this on any announcement I am sorry, otherwise it makes no sense to me. Thank you 回答1: Just found out myself that there's no index.html in public any more either because it's done dynamically in Rails 4

问题 I have a model Product which has a belongs_to association with another model Type. In the product's form, I'm using formtastic to display a select tag with all the types available in the database, like this: <%= f.input :type %> The select is showing up OK, but each option of it is an object instance of the Type model as a string, for example: #<Type:0x00eff180c85c8> Instead of that, I'd like to display the 'title' attribute of it, like: Electronic Domestic ... Any ideas? 回答1: Try the member

问题 I'm having real trouble pulling out a set of records that are self-referentially related to a user in order to show these on a user's 'show' page. Here's the idea: Users ( current_user ) rate the compatibility between two other users ( user_a and user_b ). They can rate compatibility either positively or negatively: rating two users "compatible" creates a positive_connection between user_a and user_b, and rating them "incompatible" creates a negative_connection . So there are models for

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 years ago . When running with bundle exec $ time bundle exec rails generate model student name:string age:number invoke active_record create db/migrate/20121215170617_create_students.rb create app/models/student.rb real 0m13.397s user 0m11.676s sys 0m0.597s Running directly $ time rails generate model student name:string