I have a model named User and I want to be able to self reference other users as a Contact. In more detail, I want a uni-directional relationship from users to other users, and I want to be able to reference an owned user of one user as a 'contact'. ALSO, i want to have information associated with the relationship, so I will be adding fields to the usercontact relation (I just edited this sentence in).
I attempted to do this while using the answer to this question as a guide.
Here is the User model:
user.rb
class User < ActiveRecord::Base
attr_accessible(:company, :email, :first_name, :last_name,
:phone_number, :position)
has_many(:user_contacts, :foreign_key => :user_id,
:dependent => :destroy)
has_many(:reverse_user_contacts, :class_name => :UserContact,
:foreign_key => :contact_id, :dependent => :destroy)
has_many :contacts, :through => :user_contacts, :source => :contact
end
I also created the model UserContact as a part of connecting contacts to users:
usercontact.rb
class UserContact < ActiveRecord::Base
belongs_to :user, :class_name => :User
belongs_to :contact, :class_name => :User
end
Here is the create_users.rb migration file i used:
create_users.rb
class CreateUsers < ActiveRecord::Migration
def change
create_table :users do |t|
t.string :first_name
t.string :last_name
t.string :phone_number
t.string :email
t.string :company
t.string :position
t.timestamps
end
end
end
And here is the create_users_contacts.rb migration:
create_users_contacts.rb
class CreateUsersContacts < ActiveRecord::Migration
def up
create_table :users_contacts, :force => true do |t|
t.integer :user_id, :null => false
t.integer :contact_id, :null => false
t.boolean :update, :null => false, :default => false
end
# Ensure that each user can only have a unique contact once
add_index :users_contacts, [:user_id, :contact_id], :unique => true
end
def down
remove_index :users_contacts, :column => [:user_id, :contact_id]
drop_table :users_contacts
end
end
However, for reasons unknown to me, I believe something has gone awry in the linking since on my users index page, I have a column using <td><%= user.contacts.count %></td>, but I get this error from the line when I attempt to load the page:
uninitialized constant User::UserContact
I think the issue may be something to do with the fact that I want to name users associated with another user as contacts, because I cannot find other examples where that is done, and as far as I can tell I am doing everything properly otherwise (similarly to other examples).
The closest similar problem that I found was outlined and solved in this question. The issue was incorrect naming of his connecting model, however I double checked my naming and it does not have that asker's problem.
Any help is appreciated, let me know if any other files or information is necessary to diagnose why this is occurring.
EDIT
After changing usercontact.rb to user_contact.rb, I am now getting this error:
PG::Error: ERROR: relation "user_contacts" does not exist
LINE 1: SELECT COUNT(*) FROM "users" INNER JOIN "user_contacts" ON "...
^
: SELECT COUNT(*) FROM "users" INNER JOIN "user_contacts" ON "users"."id" = "user_contacts"."contact_id" WHERE "user_contacts"."user_id" = 1
EDIT TWO
The issue was that my linking table, users_contacts, was misnamed, and should have been user_contacts! so I fixed it, and now it appears to work!!
You need to rename your usercontact.rb to user_contact.rb
This is naming convention rails autoload works with.
Related
I'd like to know how to solve this problem in my model/migrations, with correct referential integrity/uniqueness constraints.
I have a user table with two types of user: support_worker and service_user (like teacher and pupil). A support_worker can provide support for many service_users. I used to have separate tables for these respective user types, but for simplicity it makes more sense to have both user types in a single 'user' table (for Devise).
I'll have another table called support_allocation which records the relationship between a support_worker and the service_user(s) they support - this support_allocation has other information stored about it (like a budget; time/money). So this table needs to map one user_id to another user_id. I imagine the table structure will look something like this: SupportAllocation (id, support_worker_id, service_user_id)
So far, my migrations look like this (I've used Devise gem to create the user table so this amends it):
class ChangeUsers < ActiveRecord::Migration[5.2]
def change
change_table :users do |t|
t.string :user_type # support_worker or service_user
t.string :given_name
t.string :family_name
t.string :customer_reference # only for service_users
t.date :date_of_birth # only for service_users
t.string :job_roles # only for support_workers
end
end
class CreateSupportAllocations < ActiveRecord::Migration[5.2]
def change
create_table :support_allocations do |t|
t.boolean :active, default: true
# This next bit is guesswork
t.integer support_worker_id # support_worker's user_id
t.integer service_user_id # service_user's user_id
t.timestamps
end
end
end
Here's where I get confused... I need to create a join, but this will only do it on user_id, whereas the relationship is defined by the two user_id columns (as shown and named above). I'm not sure if this a compound key or if a single foreign key (or two) will suffice.
Here's my migration work-in-progress:
class AddJoins < ActiveRecord::Migration[5.2]
def change
change_table :support_allocations do |t|
t.belongs_to :user, index: true
end
end
end
I'd like to know how to achieve this. For the record, I'm using ActiveAdmin for my app. Thank you for your help.
I don't think you need the AddJoins migration. Add 2 associations in your CreateSupportAllocations model like so:
belongs_to :support_worker, :foreign_key => :support_worker_id, :class_name => User
belongs_to :service_user, :foreign_key => :service_user_id, :class_name => User
In your activeadmin form you can set the collections for the select, for example
(in app/admin/support_allocations.rb)
form do |f|
f.inputs do
# your inputs
f.input :support_worker, :as => :select, :collection => User.where(:user_type => 'support_worker')
f.input :service_user, :as => :select, :collection => User.where(:user_type => 'service_user')
end
f.actions
end
# added after comments
index do
selectable_column
column :support_worker
actions
end
Add a to_s method in you user model like so:
def to_s
"#{self.full_name}"
end
Thanks for all your help. I added the suggested associations to my SupportAllocation model. For the record, I also had to add the following associations to my User model to make the join work fully, in both directions:
has_many :occurances_as_support_worker, :class_name => 'SupportAllocation', :foreign_key => 'support_worker_id'
has_many :occurances_as_service_user, :class_name => 'SupportAllocation', :foreign_key => 'service_user_id'
I used the example given here to work this out.
When accessing attributes specific to a type of user (i.e. using the join over support_worker_id OR service_user_id), on the index page. I use code like this:
column 'Service user', :full_name, :sortable => 'service_users.family_name' do |support_allocation|
#ServiceUser.find(support_allocation.service_user_id).full_name
support_allocation.service_user.full_name
end
column 'Support worker', :full_name, :sortable => 'support_workers.family_name' do |support_allocation|
support_allocation.support_worker.full_name
end
Model:
class UserPosition < ApplicationRecord
belongs_to :user
belongs_to :job_title
end
UserPosition's schema:
t.integer :user_id
t.integer :company_id
t.integer :industry_id
t.integer :department_id
t.integer :job_title_id
t.string :job_title_custom
user_positions_controller.rb
def create
#user_position = UserPosition.find_or_create_by(user_id: current_user.id)
#user_position.update_attributes({
:industry_id => params[:industry_id],
:department_id => params[:department_id],
:job_title_id => params[:job_title_id],
:job_title_custom => params[:job_title_custom]
})
I need UserPosition to either create a record with:
user_id
job_title_custom
OR
t.integer :user_id
t.integer :company_id
t.integer :industry_id
t.integer :department_id
t.integer :job_title_id
Currently, if I try to create a UserPosition with just user_id & job_title_custom
It doesn't work, the logs show ROLLBACK the error message is:
#messages={:job_title=>["must exist"]}
What am I doing wrong here? I think it could be because job_title has a relationship defined in the model but the Rails Guide says that they are optional, so I'm not sure.
Turns out this is a new Rails 5 behavior.
"In Rails 5, whenever we define a belongs_to association, it is required to have the associated record present by default after this change.
It triggers validation error if associated record is not present."
"In Rails 4.x world To add validation on belongs_to association, we need to add option required: true ."
"Opting out of this default behavior in Rails 5. We can pass optional: true to the belongs_to association which would remove this validation check."
Full Answer: http://blog.bigbinary.com/2016/02/15/rails-5-makes-belong-to-association-required-by-default.html
EDIT3:
To wit, DO NOT put migration code in your model.rb files!!!
EDIT2: THE QUESTION (?) :
does ANY migration code belong in a model.rb file?
EDIT: Just mentioning extra (system/config/etc) information that I need to share in order to get a good answer to this question from someone (even if it's not you) would be greatly appreciated. (1-ups for good tips on stack overflow optimization strategies)
First of all, here is the command prompt activity:
C:\Users\davo\Desktop\RailsProjects\simple_cms>rails c
Loading development environment (Rails 3.2.3)
irb(main):001:0> subject = Subject.find(1)
←[1m←[36mSubject Load (1.0ms)←[0m ←[1mSELECT `subjects`.* FROM `subjects` WHERE `subjects`.`id` = 1
LIMIT 1←[0m
=> #<Subject id: 1, name: "Initial Subject", position: 1, visible: true, created_at:"2012-05-18 01:00:26", updated_at: "2012-05-18 01:11:21">
irb(main):002:0> subject.pages
(Object doesn't support #inspect)
The basic schema is that we have two models here, page.rb and subject.rb. Subject is the parent of Page, as you will see. Here are the two models.
Guide to viewing this code: I think all that is relevant to this problem in these two models are the has_many and belongs_to tags. And I admit, I feel like there should be some foreign keys here. Should there be foreign keys here? Or is that wrong too?
subject.rb
class Subject < ActiveRecord::Base
# attr_accessible :title, :body
has_many :pages
scope :visible, where(:visible => true)
scope :invisible, where(:visible => false)
scope :search, lambda {|query| where(["name LIKE ?", "%#{query}%"])}
end
page.rb
class Page < ActiveRecord::Base
has_many :sections
belongs_to :subject
# attr_accessible :title, :body
create_table "Pages" do |t|
t.string "name"
t.string "permalink"
t.integer "position"
t.boolean "visible?"
end
end
I'm really new at this, so please forgive me if I didn't give you some piece of information that you need. Please let let know what extra information you need, I'm not sure where the error is coming from but I know this is a model (M....VC) issue. 95% on that one.
You have a migration in your model.
create_table "Pages" do |t|
t.string "name"
t.string "permalink"
t.integer "position"
t.boolean "visible?"
end
Should be in ./db/migrate/{timestamp}_create_pages.rb. This file was generated for you if you did rails g model page
You also need a subject_id column to store the relation to subject
class CreatePages < ActiveRecord::Migration
def change
create_table :pages do |t|
t.integer :subject_id
t.string :name
t.string :permalink
t.integer :position
t.boolean :visible?
t.timestamps
end
end
end
I'm trying to figure out a complex relation between a Model.
I have a model called "Concept", which has two inheriting types called "Skill" and "Occupation". Basicly this means that each concept represents a category, but a concept can also be a skill or an occupation when going deep enough into the hierychal tree.
I'm solving this hierachy by using STI. So my schema for the Concepts table looks like this:
class CreateConcepts < ActiveRecord::Migration
def self.up
create_table :concepts do |t|
t.string :uri, :null => false, :length => 255
t.string :type, :null => true, :length => 255
t.integer :isco_code, :null => true
t.timestamps
end
end
def self.down
drop_table :concepts
end
end
The type column determins whether the Concept is a real "Concept" or a "Skill"/"Occupation".
The problem now however the following relations:
EDIT:
A Concept can belong to a single parent Concept
An Occupation can belong to a single parent Concept
A Skill can belong to multiple parent Concepts
A skill has no children
An occupation has no children
so basicly you'd have something like this:
> concept1
> concept2 concept3
> concept4 concept5 concept6 concept7 skill1
> occup1 skill2 occup2 skill5
> occup7 skill2 occup3 skill4
> occup4 skill1 occup8
I hope the picture is a bit clear what I'm trying to explain.
Currently I have created the following migration to try to solve the parent-child relation but I'm not sure how to map this with the associations...
class CreateConceptLinks < ActiveRecord::Migration
def self.up
create_table :concept_links do |t|
t.integer :parent_id, :null => false
t.integer :child_id, :null => false
t.timestamps
end
end
def self.down
drop_table :concept_links
end
end
What I want to end up with is the following posssibilities:
concepta.parents => a Concept object
conceptb.children => an array of Conept objects
Occupation.parents => a Concept object
Occupation.children => []
Skill.parents => an array of Concept objects
Skill.children => []
Hope this is even possible...
You can model hierarchical relations in rails. You've got most of the way there with your migrations. Adding the relations below should allow you to do the method calls you'd like:
def Concept < ActiveRecord::Base
has_many :child_links, :class_name => 'ConceptLink', :foreign_key => 'parent_id'
has_many :children, :through => :child_links
has_many :parent_links, :class_name => 'ConceptLink', :foreign_key => 'child_id'
has_many :parents, :through => :parent_links
end
def ConceptLink < ActiveRecord::Base
belongs_to :child, :class_name => "Concept"
belongs_to :parent, :class_name => "Concept"
end
I'd also take a look at this blog posting which does a very good of explaining parent-child mappings in rails.
I've been trying to setup a Single Table Inheritance model in Rails 3 in which the parent class also contains a has_many relationship. Unfortunately I can't get it to work. Here are three classes as an example:
class Article < ActiveRecord::Base
has_many :paragraphs, :dependent => :destroy, :autosave => true
end
class Paragraph < ActiveRecord::Base
belongs_to :article
end
class SportsArticle < Article
end
And here's the migration that would be used to set this up:
class AddTables < ActiveRecord::Migration
def self.up
create_table :articles do |t|
t.string :type, :null => false # for STI
t.string :title, :null => false
t.timestamps
end
create_table :paragraphs do |t|
t.references :article, :null => false
t.timestamps
end
end
def self.down
drop_table :articles
drop_table :paragraphs
end
end
When I set it up this way and I try to create a new SportsArticle, say by doing the following:
SportsArticle.create(:title => "Go Giants")
I always get the following error:
"TypeError: can't convert String into Integer"
I have no idea how to fix this issue and have tried finding a solution online to no avail. Does anybody who has experience with STI models see anything wrong? Here's the link to the documentation on the create method if it will help in diagnosing the problem:
http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-create
Try renaming :type to something else, like :article_type
eg:
t.string :article_type, :null => false # for STI
The error was being caused due to a naming collision. I was using a name for one of my models called "attributes" which was causing the problem. The hint that eventually diagnosed the problem came from the Rails Association Documentation.