I have an active_admin table called shows that acts of a list of rsvps for bike riders and bike shows that the riders will compete in. The following code correctly sorts the table alphabetically by rider_last_name:
config.sort_order = 'rider_last_name_asc'
Now when a rider is attending multiple bike shows, I want the table to first sort by rider_last_name and then within that rider sort by an attribute of shows called start_time. start_time is a DateTime. According to this stackoverflow article, the following should work:
config.sort_order = 'rider_last_name_asc, start_time_asc'
but it doesn't. In fact, it undoes the sorting by rider_last_name. How do I sort by both columns?
You may try refine apply_sorting method for collections, like this:
controller do
def apply_sorting(chain)
params[:order] ? chain : chain.reorder(rider_last_name: :asc, start_time: :asc)
end
end
ActiveAdmin suggests overwrite the find_collection method, which returns an ActiveRecord::Relation. But I prefer add the order to it's output.
ActiveAdmin.register Show do
controller do
def find_collection(options = {})
super.reorder(rider_last_name: :asc, start_time: :asc)
end
end
...
end
Although it works, this overwrite the user option of click on a column.
Alternative
You can do the same with scoped_collection, which is called at the start of find_collection, but it does not work unless you add active_admin_config.sort_order = '' to the controller. This way:
controller do
active_admin_config.sort_order = ''
def scoped_collection
super.reorder(rider_last_name: :asc, start_time: :asc)
end
end
Now, if we want to reorder before and, after that take care of the user params (and do not overwrite them). This is the way.
Note: I did use active_admin_config.sort_order and not config.sort_order.
Also, the sort_order option, ends as a param of OrderClause.new call, which expect for only one sort field, see here and here.
you can try to pass an array to it as such:
config.sort_order = [:rider_last_name_asc, :start_time_asc]
Related
I have a database query where I want to get an array of Users that are distinct for the set:
#range is a predefinded date range
#shift_list is a list of filtered shifts
def listing
Shift
.where(date: #range, shiftname: #shift_list)
.select(:user_id)
.distinct
.map { |id| User.find( id.user_id ) }
.sort
end
and I read somewhere that for readability, or isolating for testing, or code reuse, you could split this into seperate methods:
def listing
shiftlist
.select(:user_id)
.distinct
.map { |id| User.find( id.user_id ) }
.sort
end
def shift_list
Shift
.where(date: #range, shiftname: #shift_list)
end
So I rewrote this and some other code, and now the page takes 4 times as long to load.
My question is, does this type of method splitting cause the database to be hit twice? Or is it something that I did elsewhere?
And I'd love a suggestion to improve the efficiency of this code.
Further to the need to remove mapping from the code, this shift list is being created with the following code:
def _month_shift_list
Shift
.select(:shiftname)
.distinct
.where(date: #range)
.map {|x| x.shiftname }
end
My intention is to create an array of shiftnames as strings.
I am obviously missing some key understanding in database access, as this method is clearly creating part of the problem.
And I think I have found the solution to this with the following:
def month_shift_list
Shift.
.where(date: #range)
.pluck(:shiftname)
.uniq
end
Nope, the database will not be hit twice. The queries in both methods are lazy loaded. The issue you have with the slow page load times is because the map function now has to do multiple finds which translates to multiple SELECT from the DB. You can re-write your query to this:
def listing
User.
joins(:shift).
merge(Shift.where(date: #range, shiftname: #shift_list).
uniq.
sort
end
This has just one hit to the DB and will be much faster and should produce the same result as above.
The assumption here is that there is a has_one/has_many relationship on the User model for Shifts
class User < ActiveRecord::Base
has_one :shift
end
If you don't want to establish the has_one/has_many relationship on User, you can re-write it to:
def listing
User.
joins("INNER JOIN shifts on shifts.user_id = users.id").
merge(Shift.where(date: #range, shiftname: #shift_list).
uniq.
sort
end
ALTERNATIVE:
You can use 2 queries if you experience issues with using ActiveRecord#merge.
def listing
user_ids = Shift.where(date: #range, shiftname: #shift_list).uniq.pluck(:user_id).sort
User.find(user_ids)
end
So I'm trying to organize one of my views so that the articles of my website are listed by the name of the title. For example some of my articles are named "article pt.1, history pt.2, society pt.1, etc". I do have them sorted correctly using this line of code in the Articles controller
def index
#articles = Article.order(:user_id)
end
It does work using the user id, but if I wanted to add another category and have them in alphabetical order, I would need to update the user id of each article which is not practical as they number a little over 200 in the database. What I would like to is somehow take a partial of the article title and sort each one like I am with the user_id field. This way I can sort each one using the string partial such as "article" from "article pt.1"
Thank you for reading and have a wonderful day!
Why not just sort by the title? Assuming you have a column in your articles table called title:
For alphabetical order
def index
#articles = Article.order(:title)
end
For reverse alphabetical order
def index
#articles = Article.order(title: :desc)
end
If you really want to just sort by a substring of the title. You'll have to add a new column to the articles table (called slug in this example):
rails g migration AddSlugToArticles slug:text
rails db:migrate
Then you'll have to update the slug field of every record
Article.all.each do |article|
new_slug = #your code to generate substring here
article.update(slug: my_string
end
then order by slug:
def index
#articles = Article.order(:slug)
end
First of all, it is not very clear about the output that you want, but based on assumption and the description mentioned in the post, it seems like you want to sort the string field not based on whole value but based on substring.
It is better to use the order to get the strings alphabetically sorted.
#articles = Article.order(:title)
And it will also serve the purpose as it will first match the first alphabet of each string and also handle null values at the same time.
Why write a custom logic if the purpose is fulfilled by an already defined method.
I was able to do it using the sort function instead of order using the :title field on the articles controller.
def index
#articles = Article.sort(:title)
end
I have a model lets say Post which has a column called published_at (datetime). My model has two instance methods called next and prev.
I'm using mysql as a database adapter.
def next
self.class.unscope(:order).online
.where('published_at > ?', published_at)
.order('published_at ASC').first
end
def prev
self.class.unscope(:order).online
.where('published_at < ?', published_at)
.order('published_at DESC').first
end
With the code above the navigation works if every post has another date. If some posts are on the same date just one record of those gets shown.
Goal: Get the next or previous record ordered by published_at datetime column.
Any ideas?
Neither "next" , nor "previous" make sense in SQL. You have to explicitly define sort order by uniq key.
If you have non-uniq column as sort base, you have to add uniq one, id for example.
Then you have to change WHERE clause to accept rows wich have same value for your non-uniq column:
def next
condition = <<~SQL
(published_at = :published_at AND id > :id) OR
(published_at > :published_at)
SQL
self.class.unscope(:order).
online.
where(condition, published_at: published_at, id: id).
order(published_at: :asc, id: :asc).
take
end
prev is constructed similarly.
I have a calculated field in my model as follows.
class Products < ApplicationRecord
attr_reader :days
def days
(Date.today - self.created_at).to_i
end
end
When I try to sort it with, I receive an error.
#products = Product.all.order("days").paginate(:page => params[:page], :per_page => 15)
Error:
PG::UndefinedColumn: ERROR: column "days" does not exist
I will appreciate if anyone can show me how to sort based on a calculated field?
Rails order clause parameter columb should be exist in the table, does not support for user defined custom attribute in the model. So, you have to use the ruby sort_by method for custom defined attributes like below,
Product.all.sort_by(&:days)
And also you have to change your method to like below,
def days
DateTime.now.to_i - self.created_at.to_i
end
It will just work but this is not a best practice to sort the records based on custom user defined custom attribute. So, you have to move this logic to sql query itself like below,
Product.all.order("now() - created_at")
It works on postgres, not sure about mysql, please check alternate in mysql if not working.
the problem for your code above is attr_reader :days, meanwhile days you declared as method not variable
here is my idea for your problem
in your model
class Products < ApplicationRecord
def total_days
(Date.today - self.created_at).to_i
end
def self.sorted_by_days
Product.all.sort_by(&:total_days).reverse
# just delete .reverse incase you want ascending
# I put reverse in case you want to sort descending
end
end
in your controller
#products = Product.sorted_by_days.paginate(:page => params[:page], :per_page => 15)
I am not sure how you are running this piece of code:
(Date.today - self.created_at).to_i
Because it expects a numeric value with the - sign. I was able to do it like this:
((Time.zone.now - self.created_at) / 1.day).to_i
But the main point is I think you want to order the records by created_at date. So by default it is ascending and you want to display the records which has been recently created first so you can do it like this directly:
Product.all.order(:created_at)
and if you want it in descending order then you can do it like this:
Product.all.order(created_at: :desc)
Still if you need to sort it by an attr_reader the other answers show how you can do it. Just the issue will be that the pagination works on ActiveRecord::Collection rather than array so for will_paginate you may refer here:
Ruby on Rails will_paginate an array
Hope this helps.
I have two tables:
Venues
has_many :venue_intel_maps
VenueIntelMap
belongs_to :venue
In the venue_intel_map table there's a column called :tag_label that I want to grab for each particular venue that has a venue_intel_map
In my controller below this returns an array of each venue where then each venue has a venue_id
def show
#venues = Venue.where(parent_venue_id: current_admin.parent_venue_id)
end
So in my views, I can do this for particular venue.
- #venues.each do |venue|
=venue.name
=venue.address
=venue.location
But because I want to get to venue_intel_maps table so I can call a column called :tag_label I wanted to avoided a nested each statement that might look something like this
- #venues.each do |venues|
- venues.venue_intel_maps.each do |intel_maps|
= intel_maps.tag_label
Is there anyway I can clean this up or any suggestions? I was trying to play around with .joins or .selects in active record but didn't know how to successfuly do that so I can somehow put the logic in my Venues model.
EDIT
Would it also be better somehow to define in the controller my venue doing this? In the views I'm going to be pulling things from my venue_intel_maps table so would this serve any advantage?
#venues = Venue.joins(:venue_intel_maps).where(parent_venue_id: current_admin.parent_venue_id)
depending on your Rails version, try:
#venues.venue_intel_maps.pluck(:tag_label)
#venues.venue_intel_maps.map(&:tag_label)
see: http://rubyinrails.com/2014/06/rails-pluck-vs-select-map-collect/
You could preload (Rails 3+) the venue_intel_maps in the controller
def show
#venues = Venue.where(
parent_venue_id: current_admin.parent_venue_id
).preload(:venue_intel_maps)
end
Then in the view, use the iteration you suggested
- #venues.each do |venue|
= venue.name
= venue.address
= venue.location
= venue.venue_intel_maps.each do |intel_maps|
= intel_maps.tag_label