activerecord

问题 Im having a problem I developed my app in my local environment and everything works as espected, but after I deployed to heroku something is not working right. I have 2 models PurchasingGroup and GroupGoal a purchasing group has many group goals, well when I create group goals for a purchasing group I can check in the console like this PurchasingGroup.last.group_goals and the result is this one [#<GroupGoal id: 130, created_at: "2015-03-25 17:09:08", updated_at: "2015-03-25 17:10:37", other

问题 I have the following classes with associations: class Customer < ActiveRecord::Base has_many :orders has_many :tickets, :through => :orders has_many :technicians, :through => :ticket has_many :services, :through => :ticket end class Order < ActiveRecord::Base belongs_to :customer has_many :tickets has_many :technicians, :through => :tickets has_many :services, :through => :tickets end class Service < ActiveRecord::Base has_many :tickets has_many :technicians, :through => :tickets has_many

问题 I have three tables: Member MemberBranch Branch The Member can have many Branch es through MemberBranch . And a Branch can have many Member s etc. What I want to be able to do is get a count of how many members a branch has. so $branch = Branch::find_by_title('London'); $branch->number_of_members; // Will equal how many members have the branch through MemberBranch How would I go about doing this? 回答1: Try this: SELECT B.*, (SELECT count(*) as total from MembersBranch where branch_id = B.id)

问题 I have a db table: ConfigID | Type | Key | Value -------------------------------------------------------------- 0 | "API" | "ClientID" | "iofoewi" 1 | "API" | "ClientSecret" | "eijfoiewjfioejfoiewjfoie" Take the following code: $data = array( array( 'Key' => "ClientID", 'Value' => $testAPICredential->ClientID ), array( 'Key' => "ClientSecret", 'Value' => $testAPICredential->ClientSecret ) ); try { $this->context->db->trans_start(); $this->context->db->update_batch( $this->tableName, $data,

问题 In the Invoice class of my Rails application I need to find all invoices that are overdue. I have only two database columns, date (which is a type datetime field) and days_allowed (which is a type integer field). This is what I've got: class Invoice < ActiveRecord::Base def self.overdue where("date + days_allowed < ?", Date.today) end end It's neither throwing an error nor returning the relation that I need, though. Is there a better way to sum two database columns and then do calculations on

问题 In the Invoice class of my Rails application I need to find all invoices that are overdue. I have only two database columns, date (which is a type datetime field) and days_allowed (which is a type integer field). This is what I've got: class Invoice < ActiveRecord::Base def self.overdue where("date + days_allowed < ?", Date.today) end end It's neither throwing an error nor returning the relation that I need, though. Is there a better way to sum two database columns and then do calculations on

问题 I'm trying to figure out how to create a new profile for the user that has just been created, I'm using devise on the User model, and the User model has a one to one relationship with the UserProfile model. Here's what my User Model looks like: class User < ActiveRecord::Base has_and_belongs_to_many :roles belongs_to :batch has_one :user_profile after_create :create_user_profile def create_user_profile self.user_profile.new(:name => 'username') end # Include default devise modules. Others

问题 I have a form with 10 attributes. Among them I have 4 attributes which I need to apply what I'd call a"mutually conditional presence" Active Record validation. I want that (A) if one at least is present, then the other 3 must be present (B) still allow none to be present (if the other 3 are blank, then the fourth has the right be be blank) Here are the four attributes: address_line_1 zipcode state country It means that if the user fills ONE of them then ALL the others have to be present. But

问题 I have a form with 10 attributes. Among them I have 4 attributes which I need to apply what I'd call a"mutually conditional presence" Active Record validation. I want that (A) if one at least is present, then the other 3 must be present (B) still allow none to be present (if the other 3 are blank, then the fourth has the right be be blank) Here are the four attributes: address_line_1 zipcode state country It means that if the user fills ONE of them then ALL the others have to be present. But

问题 Following is the association between 2 models: class FotoGossip < ActiveRecord::Base has_many :uploads end class Upload < ActiveRecord::Base belongs_to :foto_gossip end @latest_uploads = Upload.all(:include => :foto_gossip, :order => "created_at DESC", :limit => 5) It displays the latest 5 photos from Upload model. But, I want to display 5 images from Uploads, order_by created_date DESC but only 1 image per FotoGossip. Its something like grouping the recent FotoGossip with its one photo from