if statement in ruby loop editing properties - ruby-on-rails

I have two database tables, user and product
When the user creates a product the user.id is placed into the product table under product.user_id
I'm writing a loop to displays all products "belonging" to the currently signed in user, it looks like this so far.
<% #product.each do |p| %>
<% if product.user_id = user.id %>
<tr>
<td><%= user.id %></td>
<td><%= product.user_id %></td>
<td><%= product.id %></td>
<td><%= product.name %></td>
</tr>
<% end %>
<% end %>
If the currently signed in user is user 2 for example, instead of filtering all products that don't have a user.id of 2 it just changes the product.user_id for every product to 2 so that the returned table looks like so.
2 2 1
2 2 2
2 2 3
2 2 4
Without the if statement it returns the full product listing with all the correct properties.

You should use == not =:
<% if product.user_id == user.id %>

Here is your complete solution
<% #product.each do |p| %>
<% if p.user_id == user.id %>
<tr>
<td><%= user.id %></td>
<td><%= p.user_id %></td>
<td><%= p.id %></td>
<td><%= p.name %></td>
</tr>
<% end %>
<% end %>
However I don't know what is going on in your controller but you could probably save a lot of effort by filtering out on the current user's products in the controller prior to serving that #product instance variable to the view. Maybe try a query like this:
user_id = current_user.id #assuming you have access to a method like this
#product = Product.where(user_id: user_id)
EDIT
philomor is correct. You should add a has many relationship on user see below.
#app/models/user.rb
class User < ActiveRecord::Base
has_many :products
end
#app/models/product.rb
class Product < ActiveRecord::Base
belongs_to :user
end
However not that you have this relationship you want to be carful that when you call it you don cause an N+1 query. To avoid this do the following when fetching all of a user’s products
#products = User.find(params[:user_id]).includes(:products).products

Use a comparison operator == and your if statement should be something like
<% if p.user_id = user.id %>

Related

Iterate id from the controller rails

How can I iterate in the controller, I want to replace the view and create object an for #reserve = Reserve.where(:user_id=>user.id), how can I get each user.id from #user_list = User.where.not(id: 1) and output the view as
<% #reserve.each do |a| %>
<td><%= a.date %></td>
<td><%= a.time %></td>
<% end %>
Model
class Reserve < ApplicationRecord
belongs_to :user, optional: true
end
View
<% #user_list.each do |user| %>
<td><%= user.name %></td>
<% Reserve.where(:user_id=>user.id).each do |a| %>
<td><%= a.date %></td>
<td><%= a.time %></td>
<% end %>
Controller
#user_list = User.where.not(id: 1)
The reason why I want to do it this way is because I am using a gem for sorting
and I want to place the sort on their respective model instead of using User for both reserve and user which would cause an error.
when /^created_at_/
order("user.created_at #{ direction }")
If I understand your question (which I'm not sure I do), in your controller, do something like:
#user_list.each do |user|
#user = user
#reserve = Reserve.where(user: user) # <= do some sorting around here
render partial: 'user_list'
end
Now, you'll have #user and #reserve available in a partial, something like:
# _user_list.html.erb
<td><%= #user.name %></td>
<% #reserve.each do |a| %>
<td><%= a.date %></td>
<td><%= a.time %></td>
<% end %>

Displaying has and belongs to many associations in index

Hey I'm new to Rails and all this so bear with me, thanks!
I have two models:
class User < ApplicationRecord
has_and_belongs_to_many :sports
end
class Sport < ApplicationRecord
has_and_belongs_to_many :users
end
My users have a few different sports that they can choose each. I'm simply trying to display all users in a table, along with which sports they do. However.. the only way I've managed to get anything without an error is by using current_user as shown below. I've been looking how to do this for hours... I know it's going to be stupidly simple but I just can't figure it out or even know how to go in the right direction.
# users_controller.rb
def index
#users = User.all
#sports = current_user.sports
end
# users/index.html.erb
<% #users.each do |user| %>
<tr>
<td><%= link_to user.name, user %></td>
<td><%= link_to user.email, user %></td>
<% #sports.each do |s| %>
<td><%= s.name %></td>
<% end %>
</tr>
<% end %>
That's my current code but obviously this shows only the signed in users associations and repeats it for the other users like this:
<table>
<tr>
<th>Name</th>
<th>Sport 1:</th>
<th>2:</th>
</tr>
<tr>
<td>User 1 (current_user)</td>
<td>Football</td>
<td>Running</td>
</tr>
<tr>
<td>User 2</td>
<td>Football (User 1's Sports)</td>
<td>Running </td>
</tr>
</table>
Thanks in advance.
You can try using the following and deleting #sports = current_user.sports:
<% user.sports.each do |s| %>
<td><%= s.name %></td>
<% end %>
using user.sports while looping through each of the user will lead to N+1 queries on your database. You can change your controller method to something like
def index
#users = User.all.eager_load(:sports)
end
and then in html
<% user.sports.each do |s| %>
<td><%= s.name %></td>
<% end %>
This will load users along with left_outer_join on sports table and this will save to lot of extra queries on your database.
For Info you can refer this good blog.
Thanks

Generate attendance view/form in rails for all students

I am new to Rails and I am struggling on something which sounds easy but can not get it to work. I have two models Students and Attendances.
Student model:
name lastname classroom_id
Attendance model:
present:boolean absent:boolean halfday:boolean attnd_date:date student_id
Students has_many :attendances and attendance belongs_to :student.
I can make an entry for individual student and take their attendance however I want to generate a view where I show all the students (or show all students for a given classroom) and next to each student name I would like to show the three checkboxes so that I can mark who is present and absent in one go rather than one by one and submit the form.
Any help here is much appreciated. Using Rails 4 and ruby 2.2.0
Thanks
You can make an edit action, where you will find the classroom for which you want to mark attendances.
class AttendancesController < ApplicationController
def edit
#classroom = Classroom.find(<classroom-id>)
end
def update
end
end
In your view edit.html.erb
<%= form_for(#classroom, url: '/attendances/:id', method: :put) do |f| %>
<table>
<%- #classroom.students.each do |student| %>
<tr>
<td><%= student.name %></td>
<td><%= checkbox_tag "attendances[#{student.id}][present]" %></td>
<td><%= checkbox_tag "attendances[#{student.id}][absent]" %></td>
<td><%= checkbox_tag "attendances[#{student.id}][halfday]" %></td>
</tr>
<% end %>
</table>
<%= f.submit %>
<% end %>
This way, when you submit the form, you will receive these params in your update action:
`{ attendances: { '1' => { present: false, absent: true, halfday: false }, '2' => { present: true, absent: false, halfday: false }, ... } }`.
Then you can write logic in your action to save these details to database.
Note: This is kind of pseudo code. Please check the syntax and options for different html tags.
Thanks to #Jagdeep Singh for getting me up and running. I have now made the process more simple so I can get my head around. I just want to get the list of all students and create their attendances.
My view:
<% #students = Student.all %>
<%= form_for(:attendances, url: '/admin/attendances/') do |f| %>
<table>
<%= #today %>
<th>Name</th><th>Present</th><th>Absent</th><th>halfday</th>
<%- #students.each do |student| %>
<tr>
<td><%= student.first_name %></td>
<td><%= check_box_tag "attendances[#{student.id}][present]" %></td>
<td><%= check_box_tag "attendances[#{student.id}][absent]" %></td>
<td><%= check_box_tag "attendances[#{student.id}][halfday]" %></td>
</tr>
<% end %>
</table>
<%= f.submit %>
<% end %>
when I click on create attendance button it just creates just one with record with all default params and.
I am sorry I am still learning but once I get my head around on how I can create attendances for all 10 students i have in one go.

Show attribute value using its id

In my application, I am grouping my objects by an ID. At the moment, I can only display the ID, but I would like to display the attribute value.
A Fixture belongs_to a tournament and a tournament has_many fixtures.
Controller
def index
#fixtures = Fixture.all
#tournament_fixture = #fixtures.group_by {|f| f.tournament_id}
end
View
<% #tournament_fixture.sort.each do |tourn_name, fixture| %>
<%= tourn_name %>
<% fixture.each do |f| %>
<td><%= f.home_team %></td>
<td><%= f.away_team %></td>
<td><%= f.kickoff_time %></td>
</tr>
<% end %>
<% end %>
How can I get
<%= tourn_name %>
to display its corresponding value that is in its :name column?
At the moment in my view for example i get this returned
<tbody>
2
<tr>
<td>Tournament Name</td>
<td>Team 1</td>
<td>Team 2</td>
<td>2000-01-01 14:00:00 UTC</td>
<td><a class="btn btn-success" href="/fixtures/1">view</a></td>
</tr>
</tbody>
The 2 needs to be the value in the :name column
I'd recommend grouping by tournament instead:
#tournament_fixture = #fixtures.group_by(&:tournament)
And then iterate using:
<% #tournament_fixture.sort.each do |tournament, fixture| %>
<%= tournament.name %>
...
<% end %>
You can access the whole object much like you can get the id like this:
def index
#fixtures = Fixture.includes(:tournaments).all
#tournament_fixture = #fixtures.group_by {|f| f.tournament.name}
end
The id is still available as either f.tournament_id or f.tournament.id, should you still need it but I just figured you'd rather group by its name directly. I simply added an includes statement to also load the referenced Tournament objects with your fixtures in one go. Otherwise, Rails would load the tournaments only when you access them one by one.
As an alternative, you could load the Tournaments, including all their the fixtures instead and iterate over the tournaments like this:
Controller
def index
#tournaments = Tournament.includes(:fixtures).all
end
View
<% #tournaments.each do |tournament| %>
<%= tournament.name %>
<% tournament.fixtures.each do |f| %>
<td><%= f.home_team %></td>
<td><%= f.away_team %></td>
<td><%= f.kickoff_time %></td>
</tr>
<% end %>
<% end %>
It seems a bit more natural to me and you don't need to iterate over all fixtures to map them by their tournament.
You can load the fixtures in the right order. There is no need to group then in memory. Remember to include the tournaments to avoid N+1 queries.
# controller
def index
#fixtures = Fixture.order(:tournament_id).includes(:tournaments).all
end
Loading in the right order in the controller makes the view simpler. For the tournament's name just use the association between Fixture and Tournament.
# view
<% #fixtures.each do |fixture| %>
<tr>
<td><%= fixture.tournament.name %></td>
<td><%= fixture.home_team %></td>
<td><%= fixture.away_team %></td>
<td><%= fixture.kickoff_time %></td>
</tr>
<% end %>

Identifying Model Instance by Two Relations

I'm trying to pick out an instance of a model ("Package") by its relation to two other models to which it belongs ("Cut" and "Animal"). While there are, say many packages with :cut_id 3 and many with :animal_id 4, there should only be one with both, and I want to pick that one out and display its contents in a table.
I've tried the following DIY mess, and it's not really working. (cutfind is a method I created that I know works for calling out all of the cuts associated with the given animal.)
<% #animal.cutfind.each do |cut| %>
<tr>
<td><%= cut.name %></td>
<td><%= number_to_currency(cut.price) %></td>
<td><%= cut.package_weight %> lb</td>
<% #a = Package.where(:animal_id => #animal.id) %>
<% #pset = #a.where(:cut_id => cut.id) %>
<% #pset.each do |p| %>
<td><%= p.original %></td>
<td><%= p.left %></td>
<% end %>
</tr>
<%end%>
Any idea how to do this [better]? Thanks.
Update: I tried this other DIY mess and am getting the same problem (the cells aren't even being created, which leads me to believe that #pset is empty).
This is in my animal model:
def packagefind
Package.where(:animal_id => self.id)
end
And then I changed the above like so:
<td><%= cut.package_weight %> lb</td>
<% #pset = #animal.packagefind.where(:cut_id => cut.id) %>
<% #pset.each do |p| %>
<td><%= p.original %></td>
<td><%= p.left %></td>
<% end %>
Rails will automatically generate methods to help you find the associated records if you define the following relations:
class Animal
has_many :cuts
has_many :packages, :through => :cuts
end
class Cut
belongs_to :animal
belongs_to :package
end
class Package
has_many :cuts
has_many :animals, :through => :cuts
end
In your controller, the following line will eager load all the records you will need in your view:
#animal = Animal.includes(:cuts => :package)
Your view can then be shortened to:
<% #animal.cuts.each do |cut| %>
<tr>
<td><%= cut.name %></td>
<td><%= number_to_currency(cut.price) %></td>
<td><%= cut.package_weight %> lb</td>
<td><%= cut.package.original %></td>
<td><%= cut.package.left %></td>
</tr>
<%end%>
As I'm not able to comment on your post, I take a guess:
You have the folllowing architecture:
Cut -> Package <- Animal
In this, "->" and "<-" are one-to-many relationships so that
class Package < ActiveRecord::Base
has_many :cuts
has_many :animals
end
So, you want "the" package, that has Cut with id 3 and Animal id 4.
Did you try:
x = Product.select { |product| product.cuts.include?(Cut.find(3)) }.select{ |product| product.animals.include?(Animal.find(4)) }
?
EDIT: I first suggested to you use
Product.find_by_product_id_and_animal_id()
which didn't work but showed the OP the way to do it

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