activerecord

问题 I have a page that has several "Feeds". In my controller I have something like this: def index @plays = current_user.plays.includes(:game).order("created_at desc") @wants = current_user.wants.includes(:game).order("created_at desc") @ratings = current_user.ratings.includes(:game).order("created_at desc") end and I use code like this in the view: <% @plays.each do |play| %> You played <%= play.game.name %></p> <% end %> Now I want to make a forth feed on the page that is "all activity" which

问题 if tried to access paperclip images from another model to show in its view through a sql query, it wont show the images. i tried something like this from a category controller wch takes in params from a form, in the index page, thru select box. category controller def show @category = Category.find_by_sql ["select distinct l.* from listings l , categories c, categories_listings cl where c.id = cl.category_id and l.id = cl.listing_id and c.id in (?,?)" , params[:c][:id1] , params[:c][:id2]]

问题 I am writing my first program with Codeigniter, and have run into a problem. I will start with a focused description of the problem and can broaden it if I need to: I need to write a multi-dimensional array to the DB and want to use the insert_batch function from the CI_DB_active_record class to do so. The problem is that I need to write empty values as NULL for some fields while other fields need to be empty strings. The current function wraps all values with single quotes, and I cannot find

问题 I have a model Student and a controller Students. In the controller I have a new method def new @student = Student.new end I then have a /views/students/new.html.haml that freaks out by using the @student. I get the error undefined method `[]' for nil:NilClass This is the haml for it %h1 Students#new %p Find me in app/views/students/new.html.haml = form_for(@student) do |f| = f.text_field :email = f.button "Submit" If I replace @student with Student.new I get the same results. However if I

问题 I know this question has been asked before on Stack Overflow, but the answers aren't doing it for me in ways I can explain. My general approach was inspired by this tutorial. What I'm trying to do, is create a really simple model for friending users that creates an equivalent friendship on both ends with a single record. At the db level, I just have a 'friendships' table that just has a user_id, a friend_id, and an is_pending boolean column. In user.rb I've defined the relationship as: has

问题 I have a model named Article, which I am joining with TwitterShare as shown below: articles = Article.joins("LEFT OUTER JOIN twitter_shares ON articles.id = twitter_shares.article_id").where("articles.id = ? or articles.id = ?", 27165, 5632).select("articles.id, twitter_shares.user_id") When I get the articles back, and examine the Article model returned, it returns the user_id as a string, even though the column type in the twitter_shares table is an integer. Why is this? How can I make

问题 I have a small rails app, and I'm trying to get some order statistics. So I have an Admin model, and an Order model, with one-to-many association. class Admin < ActiveRecord::Base attr_accessible :name has_many :orders class Order < ActiveRecord::Base attr_accessible :operation belongs_to :admin And I'm trying to get specifical orders using this query: admins = Admin.where(...).includes(:orders).where('orders.operation = ?', 'new gifts!') That works just as expected. But when I try to make

问题 New to Yii2 nuances. Just trying to get a return from a ActiveRecord query. I realize there is probably a much easier way to do this using Yii2 conventions public function actionGet_permissions() { $sql = 'select * from auth_item where owner_user_id IS NULL'; return Auth_Item::findBySql($sql)->all(); } Errors "Response content must not be an array." I think its pretty obvious the simple set of records I'm trying to return with this function. Any help is much appreciated, and let me know if

问题 In Rails v2.3 , Ruby 1.8 , if I run a sql statement with following code in my model class: ActiveRecord::Base.connection.execute("select count(*) from cars;") How can I show the query result in server console? I tried : rslt = ActiveRecord::Base.connection.execute("select count(*) from cars;") p rslt but it only returns me "MySQL result object" on the server console, not the exact result. 回答1: There are couple ways to get mysql "answer" from your query. you can call each and it will iterate

问题 class Author has_many :books validates :email, :presence => true end class Book belongs_to :author validates :title, :presence => true end Skipping validations is easy: a = Author.new a.save(:validate => false) However, I need skip author validations when creating a book without skipping books validations, like this: b = Book.new b.title = "A Book" b.author = Author.last b.save 回答1: I quite did not understand your question. In your example you are not creating any new author object: > b =