activerecord

问题 I am trying to simply add an HTML class if a database value returned is a specific number. Here is what I tried: <ul class="dog-sizes-list"> <li <%= if given_size == 1 then puts "class='active'" end %>><img src="/assets/dogs/dog-icon.png" width="30px" /></li> <li <%= if given_size == 2 then puts "class='active'" end %>><img src="/assets/dogs/dog-icon.png" width="40px" /></li> <li <%= if given_size == 3 then puts "class='active'" end %>><img src="/assets/dogs/dog-icon.png" width="50px" /></li>

问题 I have projects and users joined via has_many :through join model called ownerships. Each ownership has an owner_type attribute that I want to access. I want to have a way to pass a user_id to a project model and get the owner_type via the ownership join model. And visa versa I want to pass a project_id to a user model and get the owner_type via the ownership join model. Here is what I have: class Project < ActiveRecord::Base attr_accessible :name, :description has_many :ownerships has_many

问题 I want to display the sum of a column name "money" in my model Earning. In the rails console, I can easily get the sum I want Earning.sum(:money) and it shows the sum. earnings_controller.rb def index @earnings = Earning.sum(:money) end index.html.erb <p id="notice"><%= notice %></p> <h1>Earnings</h1> <table> <thead> <tr> <th>Money</th> <th colspan="3"></th> </tr> </thead> <tbody> <% @earnings.each do |earning| %> <tr> <td><%= earning.money %></td> <td><%= link_to 'Show', earning %></td> <td>

问题 I have a model with an address field that needs to be unique: class AddressMeta < AR::Base def normalize # normalize and store full_address end validates_uniqueness_of :full_address after_validation :normalize end I am passing addresses through a geocoding API to ensure that they are valid and normalized before storing. The trouble I'm running into is that I also want addresses to be unique, so there's only a single record per unique address string. Take the following addresses: 101 E 1st St

问题 I'm trying to get a basic rails app to read data out of a MS SQL Server database. In the tutorial I'm reading (snipped below), it mentions that the tables need to follow certain rules, such as the name being a pluralized and underscored, etc etc. None of the tables in my database follow that convention and that can't be changed. Is this still true? If so, what do I need to read to understand how to communicate with such tables? SNIPPET http://coding.smashingmagazine.com/2009/03/27/ultimate

问题 New to RoR, but am having a stab at building an app - and I'm looking for some advice on my db structure. I've got 4 models/tables: Users > Clients > Jobs > Tasks The app will work as follows: Users will login They can add Clients They can add Jobs to Clients They can add Tasks to Jobs So, Tasks belong to Jobs, Jobs belong to Clients, and Clients belong to Users. I want to query the DB for any one of a Client, a Job, or a Task and also make sure that it belongs to the currently logged-in User

问题 I have got model Team and I've got (i.e.) team = Team.first :offset => 20 . Now I need to get number of position of my team in db table. I can do it in ruby: Team.all.index team #=> 20 But I am sure that I can write it on SQL and it will be less expensive for me with big tables. 回答1: Assuming the order is made by ID desc: class Team < ActiveRecord::Base def position self.class.count(:conditions => ['id <= ?', self.id]) end end 回答2: I'm not sure I'm following along, but will position value be

问题 I have a Family class that includes a mother_id and a father_id . From the Family model's perspective, it's important to know which parent is the mother and which is the father, but the mother and father as Residents have all the same attributes (i.e. database columns). So ideally, I'd like my model files to look like this: class Resident < ActiveRecord::Base has_one :family, :dependent => :nullify, :foreign_key => :father_id has_one :family, :dependent => :nullify, :foreign_key => :mother_id

问题 I'm maintaining a rails 2.1 application that has some unfortunate choices for column names. For instance, an Event has a start and an end date. Instead of using start_at and end_at the original design uses start and end . Of course this leads to def end read_attribute(:end) || 1.hour.from_now end I'm surprised this even parses. Is this legal ruby? The real issue is that erb is blowing up with 'stack level too deep' when running a backgroundrb job to send the reminder emails. The template is <

问题 If I want a list of all the shops that are open on Sunday, I do Shop.includes(:opening_times).where("opening_times.day =?", 'Sunday') Is there any way to get a list of all the shops that are closed on Sundays? That is, all the shops that are not associated with a record where the day column is 'Sunday'? 回答1: sun_open = Shop.includes(:opening_times).where("opening times.day = ?", "Sunday").ids; sunday_closed = Shop.where("id NOT IN (?)", sunday_open); 来源： https://stackoverflow.com/questions