activerecord

问题 I have an ActiveRecord model with a status column. When the model is saved with a status change I need to write to a history file the change of status and who was responsible for the change. I was thinking an after_save callback would work great, but I can't use the status_changed? dynamic method to determine that the history write is necessary to execute. I don't want to write to the history if the model is saved but the status wasn't changed. My only thought on handling it right now is to

问题 I'm implementing a simple search function that should check for a string in either the username, last_name and first_name. I've seen this ActiveRecord method on an old RailsCast: http://railscasts.com/episodes/37-simple-search-form find(:all, :conditions => ['name LIKE ?', "%#{search}%"]) But how do I make it so that it searches for the keyword in name, last_name and first name and returns the record if the one of the fields matched the term? I'm also wondering if the code on the RailsCast is

问题 Does query execution happen at the get_where() clause of the following codeigniter active record statement? $this->db->select('*'); $q = $this->db->get_where('Contacts', array('id' => $contact_id)); $sql = $this->db->last_query(); Or does it happens once you call the result_array() ? And is $this->db->last_query(); a reliable way in getting the query string. 回答1: The query execution happens on all get methods like $this->db->get('table_name'); $this->db->get_where('table_name',$array); While

问题 I have lots of situations where I'd like to have a non-autoincrement primary key when using Rails. Example: I have one-to-one relationship between A and B. B describes some specific features added to A thus can't exist without A. So we have: A has one B B belongs to A The natural thinking would be having B.A_id as primary key. So I tried create_table b, :id=>false in migration and set_primary_key :a_id in B's model, but it doesn't create actual primary keys in the database. And I want them

问题 I'm trying to convert a "greater than" where statement to CI's Active Record syntax. When I use this snippet $this->db->join('product_stocks', "product_stocks.size_id_fk = product_attributes.id", "left"); $this->db->where('product_stocks.stock_level', '> 1'); $result = $this->db->get('product_attributes')->result_array(); Then print $this->db->last_query(); shows WHERE product_stocks . stock_level = '> 1' which is of course not correct. Can this be done? 回答1: I think this should do the trick:

问题 What's the best way to include a LIKE clause in a Rails query i.e. something along the lines of (the completely incorrect): Question.where(:content => 'LIKE %farming%') 回答1: If this is Rails 3 you can use Arel's matches . This has the advantage of being database agnostic. For example: Question.where(Question.arel_table[:content].matches("%#{string}%")) This is somewhat clunky, but easily extracted to scopes, e.g.: class Question def self.match_scope_condition(col, query) arel_table[col]

问题 Basically, I want to generate an item, in this case, a ring. I have different TYPES of rings: class Ring < ActiveRecord::Base DISPLAY_NAMES [ 'Silver', 'Gold', 'Diamond' ] attr_accessible :description, :display_name, :roll, :bonus, :total, :image, :gold end Is there a way to randomize the DISPLAY_NAMES of rings? I'm guessing something like @ring.display_name = rand(Ring::DISPLAY_NAMES) ? Is there a better way to do this? Once that is found, is there a way to set all other attributes of the

问题 This question already has an answer here : Selecting all Records if Record has any of the ID's from Array (1 answer) Closed 3 years ago . I am having trouble finding the right syntax and operator to check if a record has the same ID of any of the ID's stored in an Array. Is there a has any? function or similar? @problem = Remedy.where(["LOWER(\"remedyName\") LIKE?", "%#{params[:searchremedy]}%".downcase]).pluck(:id) @pretreatments = Treatment.joins(:remedies_treatment).where(:remedies

问题 When creating a model Deal, I use an after_create to create prizes on the DealPrize table. Deal and DealPrize have a belong to/has_many relations: a Deal has many Deal prizes and a Dealprize belongs to a Deal. It works like this: inside Deal, I have a column 'prize-number' and I use an after_create so that evetytime the amdin creates a new deal, the app takes this prize_number column, and create this volume of prizes (inserting as many rows as necessary) inside the DealPrize table. I fail to

问题 schema.rb: ActiveRecord::Schema.define(version: 20150324012404) do create_table "groups", force: :cascade do |t| t.string "title" t.integer "teacher_id" t.datetime "created_at", null: false t.datetime "updated_at", null: false end create_table "groups_students", id: false, force: :cascade do |t| t.integer "group_id" t.integer "student_id" end add_index "groups_students", ["group_id"], name: "index_groups_students_on_group_id" add_index "groups_students", ["student_id"], name: "index_groups