activerecord

问题 I'm unable to get SQL and Rails to play properly when trying to find Categories that are created each day, the past 7 days. So basically I want to find each Category sorted by the day they were created for the past 7 days. I found this on stackoverflow, but it isn't finding a Category that I just created: Category.all(:conditions => ["created_at > ? AND created_at < ?", t.at_beginning_of_day, t.tomorrow.at_beginning_of_day]) Any help? 回答1: Turns out it was UTC time difference. range =

问题 I have a pretty standard devise user model schema with roles and a many to many model for userRoles: #teacher or student create_table "roles", :force => true do |t| t.string "name" end create_table "user_roles", :force => true do |t| t.integer "user_id" t.integer "role_id" end add_index "user_roles", ["role_id"], :name => "index_user_roles_on_role_id" add_index "user_roles", ["user_id"], :name => "index_user_roles_on_user_id" create_table "users", :force => true do |t| t.string "email",

问题 I have two models: User and State. The state model has records for each of the 50 states in the United States. I would like each User to have two attributes: one "home" state, and many states to "visit". I know I have to set up some sort of model associations to achieve this, but not sure when the best approach is. Here's what I have so far, but I know there must be something wrong with have has_many and has_one association to the same model. #user.rb class User < ActiveRecord::Base has_many

问题 Before push my app to heroku, I tested my app in production mode, it works perfectly if its in the development mode, but in production mode I'm getting following error activerecord -3.1.11 Could not find table (ActiveRecord::Statement Invalid). How to fix this error? I'm sure that table 'pages' exists. C:\Sites\ecozap>rails s -e production => Booting WEBrick => Rails 3.1.11 application starting in production on http://0.0.0.0:3000 => Call with -d to detach => Ctrl-C to shutdown server Exiting

问题 This is a build on a question I asked before (without any luck). I have a model where I'm using a string as a primary key: class Employee < ActiveRecord::Base self.primary_key = "employment_id" end This table also contains the Rails default 'id' field, with a uniqueness constraint. When I add a new employee locally it all works fine, with Rails automatically generating a new unique id. However when I run this on Heroku Postgres it appears to treat 'id' and 'employment_id' as the same field. I

问题 I've been going round in circles for a few days trying to solve a problem which I've also struggled with in the past. Essentially its an issue of understanding the best (or an efficient) way to perform multiple queries on a model as I'm regularly finding my pages are very slow to load. Consider the situation where you have a model called Everything . Initially you perform a query which finds those records in Everything which match certain criteria @chosenrecords = Everything.where('name LIKE

问题 I have Lineup and Piece models joined by piece_lineup model (has many through). I added a 'status' column to the piece_lineup model but i can't figure out how to reference that attribute and/or change it. When listing the pieces associated with a lineup, I also want to list the status of the piece as it relates to the lineup. How do I do that? 回答1: It's very simple to get this column. Add to your model: has_many :pieces, through: :piece_lineup, select: "pieces.*, piece_lineup.status as status

问题 I'm trying to achieve links in my page that allow me to change the order that my posts display in. Similar to 'Recent', 'Hot' and 'Oldest' on Reddit. I currently have by default PostsController.rb def index @posts = Post.order('created_at DESC').all.paginate(page: params[:page], per_page: 20) end How would I go about adding links to a method to reverse the flow of posts to ASC or to display posts descending by a specific column on the model like views? Jon 回答1: I'd create some scopes and a

问题 I have a many to many relation in Yii2: RecipeUnit - IngredientWeight - Ingredient. In model RecipeUnit: public function getIngredientWeights() { return $this->hasMany(IngredientWeight::className(), ['recipe_unit_id' => 'id']); } public function getIngredients() { return $this->hasMany(Ingredient::className(), ['id' => 'ingredient_id']) ->via('ingredientWeights'); } Using the following code ActiveQuery generates two SQLs instead of one join, and it takes long time ( $model is a RecipeUnit

问题 I have a column called counter in my table called articles The question is how can I increment the value in this column about 1, so in the controller or model I will use update db function. E.g. I am thinking about something like this: $id = 5; //article id (I will get that from the url or db, no problem with that) $this->db->update("current counter column value plus one where id column equals $id "); And let's assume that I get the article # of views: $this->db->select_sum("counter")->get(