rails-activerecord

问题 I hit a roadblock here and need help. I want to be able to import csv file to my Active Record. Either with SmarterCSV or some other way Here is my database create_table "ques", force: true do |t| t.integer "rikt_nr" t.integer "start_nr" t.integer "end_nr" t.datetime "created_at" t.datetime "updated_at" end here is my view <h2>Import Ques</h2> <%= form_tag import_ques_path, multipart: true do %> <%= file_field_tag :file %> <%= submit_tag "Import" %> <% end %> here is my route resources :ques

问题 I have a 'tip' model and a 'team' model. I am trying to create a form where a user will select the winning teams from several games. So far the user can select the winning teams and those id's are being saved as foriegn keys in the Tip model (team_id). But after saving, I can't go (for example ) @tip.team.name . What do I need to do ? How do I associate it (I though rails might magically do it if foriegn key is set), I am very new to rails. Thanks for any help ! class Tip < ActiveRecord::Base

问题 I'm using this system for voting content in my rails app: https://github.com/twitter/activerecord-reputation-system Is there a way to make the default score for any votable item some random number for each instance. If I store something like rand(5..12) it will only pick a random default value one time, how do I get a random default value for every different row or field? create_table "rs_evaluations", :force => true do |t| t.string "reputation_name" t.integer "source_id" t.string "source

问题 I have three models in rails, Project(date, has_many :project_savings), Usage(month, amount, has_many :project_savings) and MonthlyProjectSaving(amount, belongs_to :usages, :projects). It's set up so that each project has a number of savings which correspond to a number of usages months. I'm trying to find all the project savings which have a corresponding project.date >= usage.month , and also a usage.amount == 0 in the most secure way possible. usage.month and project.date are both date

问题 If I have 3 named scopes like class Foo scope :test1, ... scope :test2, ... scope :test3, ... And a function def x(variable) end where variable is a string("test1","test2" or "test3") How can I access the named scope just by knowing that variable's value ? Something like Foo.variable 回答1: You would call Foo.public_send(variable) . 来源： https://stackoverflow.com/questions/15000854/access-named-scope-dynamically

问题 I'm trying to take advantage of bind variables in Ruby on Rails, and it doesn't need to instantiate a model, so I'm using select_all like so ActiveRecord::Base.connection.select_all( 'select * from users where id = :test', {test: 'foo'} ) But I get this big old error: ActiveRecord::StatementInvalid: OCIError: ORA-01008: not all variables bound: select * from users where id = :test from stmt.c:243:in oci8lib_220.so from /usr/local/rvm/gems/ruby-2.2.2/gems/ruby-oci8-2.2.4.1/lib/oci8/cursor.rb

问题 In my lib/tasks/data.rake, I have User.make(attributes). The make method appears to create a new record, but I cannot find any docs on this. The make method is not defined by my User model and fyi my User model inherits ActiveRecord::Base. 回答1: I 'called a friend', it turned out to be https://github.com/notahat/machinist gem 来源： https://stackoverflow.com/questions/14451397/ruby-on-rails-what-is-make-method-on-a-model

问题 I created one has_many through relationship in rails api. I also used nested routes. My models like below; class Author < ActiveRecord::Base has_many :comments has_many :posts, :through => :comments end class Post < ActiveRecord::Base has_many :comments has_many :authors, :through => :comments end class Comment < ActiveRecord::Base belongs_to :author belongs_to :post end my routes like below; Rails.application.routes.draw do namespace :api, defaults: { :format => 'json' } do resources :posts

问题 I'm using Postgres with Rails. There's a query with a subselect which returns a boolean, but Postgres always returns a String like 't' or 'f' . But in the generated JSON I need a real boolean. This is my query: SELECT *, EXISTS ( SELECT TRUE FROM measurement JOIN experiment ON measurement.experiment_id = experiment.id JOIN location ON experiment.location_id = location.id WHERE location.map_id = map.id LIMIT 1 ) AS measurements_exist FROM "map" It doesn't matter whether I use THEN true or THEN

问题 I want to validate column presence on creation method if the creation method is called from some other route. For example, If I have following two routes: post 'create_item', to: 'item#create' post 'create_verified_item', to: 'item#create_verified' I need to define in Item model something like this: validates :verified_number, presence: true, if: Item.action_name == "create_verified" Anyone can help? 回答1: Ideally you can add a attribute to item to check that, something like: # model class