I'm working on a system that tracks illnesses and symptoms associated with them through Ruby on Rails.
I have a "illnesses" table and a "symptoms" table and they have a many_to_many relationship through the "symptoms_illnesses" table.
For now, I'm working on a page that displays a single entry of the "symptoms_illnesses" table. This table has two columns: illness_id and symptom_id.
I need a way to display the illness and symptom that match the ID.
Example:
"illness" table has "Common Cold" under id = 1
"symptom" table has "Fever" under id = 1
"symptoms_illness" table has illness_id = 1 and symptom_id = 1.
I want the "symptoms_illness/1" page to display "Common Cold" and "Fever", but I see no obvious way to do it.
Other topics in this site don't seem to address the problem in a satisfactory way.
Edit 1:
I didn't add anything to the show action besides the "default"
def show
#symptoms_illness = Symptoms_illness.find(params[:id])
end
def show
#symptoms_illness = Symptoms_illness.includes(:illness,:symptom).where(id: params[:id])
end
in your view
<%= #symptoms_illness.illness.name %>
<%= #symptoms_illness.symptom.name %>
PS: not tested
After doing some research I found out how to do it:
First, I created #illness and #symptom instances to the symptom_illness_controller. Then, in the show action, I added two find_by_id.
Finally, in the Show view, I changed #symptomillness.illness_id to #symptomillness.illness.name, now it shows up fine.
This may not be the cleanest way to do it but it works for what I wanted to accomplish.
Related
I am struggling with the following problem:
I want to have two different tabs, one that displays all recent chugs (Done), and one that displays the chugs that are the fastest per person.
However, this needs to remain an ActiveRecord, since I need to use it with link_to and gravatar, thus restraining me from group_by, as far as I understand it.
AKA: If there are three users who each have three chugs, I want to show 1 chug per user, which contains the fastest time of that particular user.
The current code looks like this, where chugs_unique should be edited:
def show
#pagy, #chugs_all_newest = pagy(#chugtype.chugs.order('created_at DESC'), items: 10, page: params[:page])
#chugs_unique = #chugtype.chugs.order('secs ASC, milis ASC, created_at DESC').uniq
breadcrumb #chugtype.name, chugtypes_path(#chugtype)
end
In this case, a chug belongs to both a chugtype and user, and the chugtype has multiple chugs.
Thanks in advance!
I have a table KmRelationship which associates Keywords and Movies
In keyword index I would like to list all keywords that appear most frequently in the KmRelationships table and only take(20)
.order doesn't seem to work no matter how I use it and where I put it and same for sort_by
It sounds relatively straight forward but i just can't seem to get it to work
Any ideas?
Assuming your KmRelationship table has keyword_id:
top_keywords = KmRelationship.select('keyword_id, count(keyword_id) as frequency').
order('frequency desc').
group('keyword_id').
take(20)
This may not look right in your console output, but that's because rails doesn't build out an object attribute for the calculated frequency column.
You can see the results like this:
top_keywords.each {|k| puts "#{k.keyword_id} : #{k.freqency}" }
To put this to good use, you can then map out your actual Keyword objects:
class Keyword < ActiveRecord::Base
# other stuff
def self.most_popular
KmRelationship.
select('keyword_id, count(keyword_id) as frequency').
order('frequency desc').
group('keyword_id').
take(20).
map(&:keyword)
end
end
And call with:
Keyword.most_popular
#posts = Post.select([:id, :title]).order("created_at desc").limit(6)
I have this listed in my controller index method which allows the the order to show the last post with a limit of 6. It might be something similar to what you are trying to do. This code actually reflects a most recent post on my home page.
I've been digging around a little trying to figure out how I should locate the "tweet_id" in my #savedtweets table and then locate that same "tweet_id" in my #newtweets table from a controller, so far I'ved tried something like this;
CONTROLLER
#stweet = Savedtweet.find(params[:id])
#newtweet = Newtweet.where(:tweet_id => #stweet.tweet_id)
#newtweet.status = 'new'
#newtweet.save
Basically I need to change the string "saved" in my Newtweets table to "new" based on the current Savedtweet ID. I just can't figure it out. If I do the following in console;
#stweet = Savedtweet.first
#newtweet = Newtweet.where(:tweet_id => #stweet.tweet_id)
It finds the right one. I've got to be close just not there yet. :)
You could do:
Newtweet.find_by_tweet_id(#stweet.tweet_id).update_attribute(:status, 'new')
The reason your code isn't working is because Newtweet.where() returns an array of objects. It should be Newtweet.where().first, though Newtweet.find_by_tweet_id is the preferred method.
Is there a better way to update more record in one query with different values in Ruby on Rails? I solved using CASE in SQL, but is there any Active Record solution for that?
Basically I save a new sort order when a new list arrive back from a jquery ajax post.
#List of product ids in sorted order. Get from jqueryui sortable plugin.
#product_ids = [3,1,2,4,7,6,5]
# Simple solution which generate a loads of queries. Working but slow.
#product_ids.each_with_index do |id, index|
# Product.where(id: id).update_all(sort_order: index+1)
#end
##CASE syntax example:
##Product.where(id: product_ids).update_all("sort_order = CASE id WHEN 539 THEN 1 WHEN 540 THEN 2 WHEN 542 THEN 3 END")
case_string = "sort_order = CASE id "
product_ids.each_with_index do |id, index|
case_string += "WHEN #{id} THEN #{index+1} "
end
case_string += "END"
Product.where(id: product_ids).update_all(case_string)
This solution works fast and only one query, but I create a query string like in php. :) What would be your suggestion?
You should check out the acts_as_list gem. It does everything you need and it uses 1-3 queries behind the scenes. Its a perfect match to use with jquery sortable plugin. It relies on incrementing/decrementing the position (sort_order) field directly in SQL.
This won't be a good solution for you, if your UI/UX relies on saving the order manually by the user (user sorts out the things and then clicks update/save). However I strongly discourage this kind of interface, unless there is a specific reason (for example you cannot have intermediate state in database between old and new order, because something else depends on that order).
If thats not the case, then by all means just do an asynchronous update after user moves one element (and acts_as_list will be great to help you accomplish that).
Check out:
https://github.com/swanandp/acts_as_list/blob/master/lib/acts_as_list/active_record/acts/list.rb#L324
# This has the effect of moving all the higher items down one.
def increment_positions_on_higher_items
return unless in_list?
acts_as_list_class.unscoped.where(
"#{scope_condition} AND #{position_column} < #{send(position_column).to_i}"
).update_all(
"#{position_column} = (#{position_column} + 1)"
)
end
I'm wondering if anyone has experience using Ransack with HABTM relationships. My app has photos which have a habtm relationship with terms (terms are like tags). Here's a simplified explanation of what I'm experiencing:
I have two photos: Photo 1 and Photo 2. They have the following terms:
Photo 1: A, B, C
Photo 2: A, B, D
I built a ransack form, and I make checkboxes in the search form for all the terms, like so:
- terms.each do |t|
= check_box_tag 'q[terms_id_in][]', t.id
If I use: q[terms_id_in][] and I check "A, C" my results are Photo 1 and Photo 2. I only want Photo 1, because I asked for A and C, in this query I don't care about B or D but I want both A and C to be present on a given result.
If I use q[terms_id_in_all][] my results are nil, because neither photo includes only A and C. Or, perhaps, because there's only one term per join, so no join matches both A and C. Regardless, I want just Photo 1 to be returned.
If I use any variety of q[terms_id_eq][] I never get any results, so I don't think that works in this case.
So, given a habtm join, how do you search for models that match the given values while ignoring not given values?
Or, for any rails/sql gurus not familiar with Ransack, how else might you go about creating a search form like I'm describing for a model with a habtm join?
Update: per the answer to related question, I've now gotten as far as constructing an Arel query that correctly matches this. Somehow you're supposed to be able to use Arel nodes as ransackers, or as cdesrosiers pointed out, as custom predicates, but thus far I haven't gotten that working.
Per that answer, I setup the following ransack initializer:
Ransack.configure do |config|
config.add_predicate 'has_terms',
:arel_predicate => 'in',
:formatter => proc {|term_ids| Photo.terms_subquery(term_ids)},
:validator => proc {|v| v.present?},
:compounds => true
end
... and then setup the following method on Photo:
def self.terms_subquery(term_ids)
photos = Arel::Table.new(:photos)
terms = Arel::Table.new(:terms)
photos_terms = Arel::Table.new(:photos_terms)
photos[:id].in(
photos.project(photos[:id])
.join(photos_terms).on(photos[:id].eq(photos_terms[:photo_id]))
.join(terms).on(photos_terms[:term_id].eq(terms[:id]))
.where(terms[:id].in(term_ids))
.group(photos.columns)
.having(terms[:id].count.eq(term_ids.length))
).to_sql
end
Unfortunately this doesn't seem to work. While terms_subquery produces the correct SQL, the result of Photo.search(:has_terms => [2,5]).result.to_sql is just "SELECT \"photos\".* FROM \"photos\" "
With a custom ransack predicate defined as in my answer to your related question, this should work with a simple change to your markup:
- terms.each do |t|
= check_box_tag 'q[id_has_terms][]', t.id
UPDATE
The :formatter doesn't do what I thought, and seeing as how the Ransack repo makes not a single mention of "subquery," you may not be able to use it for what you're trying to do, after all. All available options seem to be exhausted, so there would be nothing left to do but monkey patch.
Why not just skip ransack and query the "photos" table as you normally would with active record (or even with the Arel query you now have)? You already know the query works. Is there a specific benefit you hoped to reap from using Ransack?