I'm trying to implement a two-way has_many :through association between a User model and a Location model using a UserLocations join table. This will enable setting user locations with built in ActiveRecord methods, ie. #user.locations = [<Location 1>, <Location 2>, ...]. My goal is to not associate locations to users individually, but rather for users to add and remove them, one or more at a time, via another field: :zip_code. This means that when a user adds a zip code, ActiveRecord should insert a single record into UserLocations (something like INSERT INTO user_locations (user_id, zip_code) VALUES (1, 12345)). Then, when #user.locations is called, ActiveRecord should join by :zip_code and get the matching location(s). My current implementation works, except that one INSERT into UserLocations is generated for each location associated with a zip code.
class User < ActiveRecord::Base
has_many :user_locations
has_many :locations, through: :user_locations
end
class UserLocation < ActiveRecord::Base
belongs_to :user
belongs_to :location, primary_key: :zip_code, foreign_key: :zip_code
end
class Location < ActiveRecord::Base
has_many :user_locations, primary_key: :zip_code, foreign_key: :zip_code
has_many :users, through: :user_locations
end
Things I've tried:
validates_uniqueness_of :zip_code, scope: :user_id - just throws a validation error and prevents all record creation
has_many unique: true - doesn't prevent duplicate DB queries
add_index unique: true for (user_id, zip_code) - would at least prevent duplicate entries from being created, but I'm trying to prevent unnecessary queries entirely
Using questions like this one for guidance hasn't gotten me any closer. Is what I'm trying to do possible without using my own methods to get/set user locations?
First of all, I'm not very experienced in rails yet, but I'll still try to help :)
What I would do is not using zipcodes as a key. When a user inputs zip codes you look up the code in the Location:
#zip_code = Location.where(zipcode: user_input).first
#zip_code.user_locations.create!(user_id #some other stuff you want)
This way you store the id of the location into the user location and no duplicates are made. You can then generate user locations by joining the UserLocation and Location.
But as I said, there may be a better way of doing this as I'm beginner.
Stop me if I'm wrong :)
You have zipcodes in your locations table (i.e: 111, 222, 333) When a user selects a zipcode of '111' for him self, his record is associated with the existing locations record; but when a user selects a zipcode of '444' a new locations record is created and link to that user. Next use that selects '444' will be linked to this same record.
If my assumption if correct, you should have:
validates_uniqueness_of :zip_code (without scope) in your Location model
in your User model while creating/updating you could use Location.find_or_create_by(params[:zipcode])
This is pseudo-code (don't copy-paste it), I don't exactly know how your code is writen, but my point is for you to have a look at find_or_create, I believe it could be your solution
It looks like you have the association setup correctly.
When you have a has_many association in rails and want to do something like this:
#user.locations = [<Location 1>, <Location 2>, ...]
Rails will create individual INSERT statements for each location in the array, although it will do a bulk DELETE for you. If you want it to do bulk INSERT statements, you'll need to roll your own code or look into the activerecord-import gem to do this.
As for the duplicates, if you are only doing the above code, there shouldn't be duplicate record errors unless there are duplicates in that location array, in which case you should call uniq on it first.
Related
I have a join table joining a Client and a Setor (plural: setores) models. The relation is that a Client has_and_belongs_to_many Setores (there are three Setores, a Client can have from one to all three of them. Setores have lots of Clients).
My problem is:
In this join table I added a reference to the User model. Setores have many Users, but a relation between one client and one setor have only one user. But I don't know how to read and write this association on the clients_setores table.
My models are as follows:
class Client < ActiveRecord::Base
has_and_belongs_to_many :documents
has_and_belongs_to_many :setores
has_many :screenings
has_many :contacts
has_many :interactions, through: :contacts
validates :cnpj, uniqueness: true
class Setor < ActiveRecord::Base
self.table_name = 'setores'
has_many :documents
has_many :screenings
has_many :users
has_and_belongs_to_many :clients
attr_acessor :user_id
class User < ActiveRecord::Base
has_one :setores
has_many :clients
And the current join tables parameters that have been working appear like this on the end of Clients controller:
private
# Use callbacks to share common setup or constraints between actions.
def set_client
#client = Client.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def client_params
params.require(:client).permit(:cnpj, :pacote, :razsoc, :vencimento, user_ids:[], document_ids:[], setor_ids:[])
end
Note that "user_ids:[]" was my attempt to get it to work, which has failed so far.
In the views I use the current join tables like this (taken from /client/_form.html.erb):
<%= f.collection_check_boxes :setor_ids, Setor.where(pacote: true), :id, :setor do |b| %>
So with these checkboxes I can create an entry in the clients_setores table.
What I want to do is to be able to pick a User that belongs to a given setor_id from a drop down menu and store this relation in the join table. I did manage to make such menu appear with the following code, in the same _form.html.erb:
<%= f.collection_select :user_ids, User.where(:setor_id => 1), :id, :email %>
But when I submit the form, the values are not saved. I don't know if my problem is just that I didn't get the right way to record this association on my view or if my problem is further down in the controller (probably) and model (maybe).
Closest problem I found in SO was Rails 4 Accessing Join Table Attributes, but the association type is different (has_many/through) and there isn't a third relation involved, so I couldn't figure out how to make it work for me.
Example of many-to-many associations between three models, done with a single join table:
I start out by generating some models:
rails g model User; rails g model Setor; rails g model Client;
rails g model Joiner user_id:integer setor_id:integer client_id:integer
By the way, references is a way to add a foreign key that refers to an existing model. I.e. user:references will create a user_id column. It also adds an "index" to the foreign key, which improves the performance.
Then I add some associations to the classes
class Joiner
# columns: user_id, setor_id, client_id
belongs_to :user
belongs_to :setor
belongs_to :client
end
class User
has_many :joiners
has_many :setors, through: :joiners, source: :setor
has_many :clients, through: :joiners, source: :client
end
class Setor
has_many :joiners
has_many :users, through: :joiners, source: :user
has_many :clients, through: :joiners, source: :client
end
class Client
has_many :joiners
has_many :users, through: :joiners, source: :user
has_many :setors, through: :joiners, source: :setor
end
With this code written, you have many-to-many associations for the three models.
You can then write:
User.create; Setor.create;
Joiner.create(user_id: User.first.id, setor_id: Setor.first.id);
User.first.setors.length # => 1
This won't work for self-joins (i.e. a nested comment system), by the way, but that's not part of the question.
What I ended up doing to achieve the desired effect was to add three columns to the Client model:
userset1
userset2
userset3
This way a Client has up to three (since the field can be blank) relations with users, according to the Setores (departments) he has at his service.
This is the easiest solution in this case since I only have 3 Setores. It would not be for larger numbers.
If I had more than 3 Setores, making it impractical to keep adding columns in the Client table, I would cerate a new model just to store the relations, in this case, a table that would have, besides its unique ID, client_id, setor_id and user_id.
I am short of implementation ideas for my rails project. at this point it seems impossible to implement in rails.
I am cloning a sort of accounting software into a web app using rails framework for small manufacturing companies to keep track of their products stock in their different distribution branches.
I have 3 different models: "Product", "Branch" & "Accumulator"
class Branch < ActiveRecord::Base
has_many :accumulators
has_many :products, :through => :accumulators
end
class Product < ActiveRecord::Base
has_many :accumulators
has_many :branches, :through => :accumulators
def self.search(search)
if search
where('name LIKE ?', "%#{search}%")
end
end
class Accumulator < ActiveRecord::Base
belongs_to :product
belongs_to :branch
end
I am new to rails and after reading up on many to many associations I came across using collections to add products to a branch "#branch.products << Product.all"
Is there a possible way to use a form "number_field_tag" in the branch show view to add multiple of specific products into the join table?
eg
I want to add 10 of (Product) called "garden eggs" to a (Branch) called "lagos branch" to the (Accumulator) join table using a form in Branches show view?
Congratulations for choosing :has_many, through: you will not regret it.
Is the relationship between a product and a branch static?
Or does it change a lot?
In your Accumulator model, add an integer field called amount (count can have conflicts). Then you either create a form for your Accumulators or you add a nested form with for example Cocoon.
This way you can add Accumulators to your Branch with a certain Product and a certain amount.
Off topic:
Here is an article about why has_many through has some advantages:
http://blog.flatironschool.com/why-you-dont-need-has-and-belongs-to-many/
If you have problems with forms I can really recommend SimpleForm and for nice Javascript-assisted fields I recommend Select2.
If the table accumulators needs to save only two things: product_id, and branch_id, you can easily use has_and_belongs_to_many associations.
class Branch < ActiveRecord::Base
has_and_belongs_to_many :products, join_table: 'accumulators'
end
class Product < ActiveRecord::Base
has_and_belongs_to_many :branches, join_table: 'accumulators'
end
And now, there is no need for the third model.
As far as it goes, how to add a relationship, it's pretty easy in this case:
branch = Branch.last
branch.products << Product.create # you don't need to touch the middle table.
Instead of using number_field_tag to ask for plain ids, you can use something fancy like jQuery Chosen Plugin. This plugin will allow you to use tag like input, and will send the ids to the server separated by ,'s.
I'm trying to gather a set of data for current_user so in my controller code I have:
#user_workouts = current_user.planned_workouts
with planned_workouts being the join table b/w the user and the workouts. When I test that in console:
#user_workouts.count
I get 4.
When I do:
PlannedWorkout.count
I get 4.
But when I try using a .each loop for my #user_workouts:
#user_workouts.each do |user_workout|
puts user_workout
end
I get far more than 4, I get something like ~25, how is that possible when I tested above how many planned_workouts there are in the table and for the user themselves? I also tried deleting all of the planned_workouts so that the table is empty and created 4 new ones, and still the same outcome. Can it have anything to do with the fact that I'm using add_index in the schema?
EDIT:
My model associations:
User.rb
has_many :planned_workouts
has_many :workouts, through: :planned_workouts
Workout.rb
has_many :planned_workouts
has_many :users, through: :planned_workouts
PlannedWorkout.rb
belongs_to :workout
belongs_to :user
I'll briefly explain my situation: I have a model called "tax" which belongs_to a "user" and of which a "user" has_one.
In my users table I have a column called "tax_id" which I want to store the id of the tax model when a user creates one.
Currently, in my tax model the create function looks something like this:
class Tax < ActiveRecord:Base
belongs_to :user
tax = Tax.new(income: income, taxes: taxes, rrsp: rrsp)
tax.save
and then in the taxes_controller file, the create function looks like this:
def create
#tax = Tax.new(secure_params)
#tax.user = User.find(current_user.id)
if #tax.save
redirect_to show_tax_path(current_user.tax)
else
render :new
end
end
(secure_params) being the strong parameters for the field inputs set in a private definition.
Now, someone mentioned that I may have better luck if I use build but unfortunately I couldn't get it to work at all, something to do with how I'm using current_user (devise). Currently, my setup works just fine, other than saving the tax model id in the user model column "tax_id" like I said.
I'm wondering if I perhaps need to add a foreign ID key to either the belongs_to or has_one statement, even though I was under the impression that the "link" should be made automatically as long as the column was named "[model]_id"
try using
user.build_tax
I think this might help you out.
The build syntax for has_many association:
user.taxes.build
The build syntax for has_one association:
user.build_tax # this will work
user.tax.build # this will throw error
This is a pretty simple question really, but let's say I'm creating a model for Person. Person obviously has first name, last name, age, etc. But the person also has contact info consisting of things like address line 1, address line 2, city, state, zip, country, phone 1, phone 2, etc...
Does it make more sense to create a model for Person and then list that contact information as tables in the model or to also create, say, a ContactInfo (or Address, etc) model, then associate the Person to ContactInfo through an association (Person has_one ContactInfo/Person has_one Address/Address belongs_to Person, etc)?
Which of these is a better approach and what are the benefits/drawbacks to each method?
edit: in re to j..
So with this approach, would I have to then create an Addressable model?
script/generate model Addressable
class Addressable < ActiveRecord::Base
#stuff here?
end
or is this unnecessary?
Also, would i need to add this line to the create_users.rb:
t.references :addressable, :polymorphic => true
I feel like I'm missing something, but I'm not sure what. I appreciate the help a ton, btw! Thanks!
I'd create separated tables/models for address, phone and stuff like this and would make them polymorphic. Like this:
class Address < ActiveRecord::Base
belongs_to :addressable, :polymorphic => true
end
class Person < ActiveRecord::Base
has_one :address, :as => :addressable
end
I believe this is the best way because later you may need to add, for example, a Company model and it'll be easy to make it addressable.
Edit
Using the address as example, you'd need an Address model, not Addressable.
And you'll have to add
t.references :addressable, :polymorphic => true
or
t.belongs_to :addressable, :polymorphic => true
to your create_addresses migration, so you'll have the addressable_id and addressable_type in the addresses table.
Let me know if you have any other doubts :]
the answer above makes sense, but think about how many fields you need and how many records you have to manage. creating a table for each additional field may be too much effort.
another approach could be something more flexible: create a table (say, person_details) with 3 fields: person_id:integer, field_name:string, field_data:string, then the model:
class PersonDetail < ActiveRecord::Base
belongs_to :person
end
this way you can add whatever additional field you need: phone1..phoneN, address1..addressN, and so on.
another similar approach is to pre-determine fields names, to avoid different labels during inserts:
class PersonDetail < ActiveRecord::Base
belongs_to :person
FIELD_NAMES => { 'Address' => 1, 'Phone' => 2)
end
in this case you'll declare the field_name as integer (because it stores only the value of the hash, not a string).