Sort has_many relation in rails 3 - ruby-on-rails

my model is
class Job < ActiveRecord::Base
belongs_to :client
end
class Client < ActiveRecord::Base
has_many :jobs
end
in controller i want get client with sorted jobs.
If i do (without ordering)
#client = Client.find(params[:id], :include => {:jobs => :status})
It is all ok. But if i add ordering:
#client = Client.find(params[:id], :include => {:jobs => :status}, :order => 'job.level DESC')
// :order is dynamicly set (not in this example) - i know about :order in has_many.
the result is only 3 rows (for every job.level one). I logged the sql query and executed it and result is ok, but in app i have only these 3 rows.
What is the right way to sort jobs? Thank you

You could try specifying the order directly in the model instead of the controller
class Job < ActiveRecord::Base
belongs_to :client, :order => 'level DESC'
end
OR
class Client < ActiveRecord::Base
has_many :jobs, :order => 'level DESC'
end
Also, what data type is the level in the Jobs model? If you could post your logs for the sql queries that would be helpful as well. Also, have you tried
:order => 'jobs.level'
instead of the singular job.level used in the code you posted?

This is not what i originally wanted, but it works, so this is answer
#jobs = #client.jobs.find(:all, :order => sort_column + " " + sort_direction)

Related

How to query a collection through multiple associations?

I need to collect objects that are all connected through multiple layers of associations, and I don't know who to do so.
I need to get a collection of CustomText based on a string query param.
Basically I need to do a query that will pull a collection of CustomText by name:
#searched_content = params[:search].downcase
#query = CustomText.where("lower(name) like ?", "%#{#searched_content}%")
but then also filters the #query to only search LineItems that have been a part of an approved order. I am using Spree, where Spree::Order has_many Spree::LineItem. Basically, doing something like this (doesn't work at all, but hopefully you'll be able to see what I'm trying to do):
#query = Spree::LineItem.joins(:order).where(spree_orders: {state: "complete"}).joins(:custom_texts).where("lower(name) like ?", "%#{#searched_content}%"))
Models:
class CustomText < ActiveRecord::Base
belongs_to :custom_set, :inverse_of => :custom_texts
end
class CustomSet < ActiveRecord::Base
belongs_to :spree_line_item, :class_name => Spree::LineItem, :foreign_key => :spree_line_item_id
has_may :custom_texts, :dependent => :destroy, :inverse_of => :custom_set
end
class LineItem < ActiveRecord::Base
has_many :custom_texts, :through => :custom_sets
has_many :custom_sets, :dependent => :destroy, :foreign_key => :spree_line_item_id
end
Any help would be very appreciated.
Well, this was just a simple syntax error with one too many end parenthesis at the end...stupid spelling error.
#query = Spree::LineItem.joins(:order).where(spree_orders: {state: "complete"}).joins(:custom_texts).where("lower(name) like ?", "%#{#searched_content}%")

Rails 3.1 - Simple search across three (or more) models?

I have three models that i'd like to perform a simple search across:
class Release < ActiveRecord::Base
has_many :artist_releases
has_many :artists, :through => :artist_releases
has_many :products, :dependent => :destroy
end
class Product < ActiveRecord::Base
belongs_to :release
has_many :artists, :through => :releases
end
class Artist < ActiveRecord::Base
has_many :artist_releases
has_many :releases, :through => :artist_releases
end
In my Product Controller i can successfully render a product list searching across release and product using:
#products = Product.find(:all, :joins => :release, :conditions => ['products.cat_no LIKE ? OR releases.title LIKE ?', "%#{params[:search]}%","%#{params[:search]}%"])
I really need to be able to search artist as well. How would I go about doing that? I ideally need it within the Product Controller as it's a product list I need to display.
I've tried adding :joins => :artist and variations thereof, but none seem to work.
I'm aware there are options out there like Sphinx for a full search, but for now I just need this simple approach to work.
Thanks in advance!
if you only want products back, just add both joins:
#products = Product.joins(:release,:artists).where('products.cat_no LIKE :term OR releases.title LIKE :term OR artists.name LIKE :term', :term => "%#{params[:search]}%").all
You may also need group_by to get distinct products back.
if you want polymorphic results, try 3 separate queries.
I know I'm suggesting a simple approach (and probably not the most efficient) but it will get your job done:
I would create a method in your Product model similar to this:
def find_products_and_artists
results = []
Product.find(:all, :conditions => ['products.cat_no LIKE ?', "%#{params[:search]}%"]).each do |prod|
results << prod
end
Release.find(:all, :conditions => ['releases.title LIKE ?', "%#{params[:search]}%"]).each do |rel|
results << rel
end
Artist.find(:all, :conditions => ['artist.name LIKE ?', "%#{params[:search]}%"]).each do |art|
results << art
end
return results
end
Then when you call it the method and store the returned results in a variable (e.g. results), you can check what object each element is by doing
results[i].class
and can make your code behave accordingly for each object.
Hope I helped.

Rails model relations depending on count of nested relations

I am putting together a messaging system for a rails app I am working on.
I am building it in a similar fashion to facebook's system, so messages are grouped into threads, etc.
My related models are:
MsgThread - main container of a thread
Message - each message/reply in thread
Recipience - ties to user to define which users should subscribe to this thread
Read - determines whether or not a user has read a specific message
My relationships look like
class User < ActiveRecord::Base
#stuff...
has_many :msg_threads, :foreign_key => 'originator_id' #threads the user has started
has_many :recipiences
has_many :subscribed_threads, :through => :recipiences, :source => :msg_thread #threads the user is subscribed to
end
class MsgThread < ActiveRecord::Base
has_many :messages
has_many :recipiences
belongs_to :originator, :class_name => "User", :foreign_key => "originator_id"
end
class Recipience < ActiveRecord::Base
belongs_to :user
belongs_to :msg_thread
end
class Message < ActiveRecord::Base
belongs_to :msg_thread
belongs_to :author, :class_name => "User", :foreign_key => "author_id"
end
class Read < ActiveRecord::Base
belongs_to :user
belongs_to :message
end
I'd like to create a new selector in the user sort of like:
has_many :updated_threads, :through => :recipiencies, :source => :msg_thread, :conditions => {THREAD CONTAINS MESSAGES WHICH ARE UNREAD (have no 'read' models tying a user to a message)}
I was thinking of either writing a long condition with multiple joins, or possibly writing giving the model an updated_threads method to return this, but I'd like to see if there is an easier way first. Am I able to pass some kind of nested hash into the conditions instead of a string?
Any ideas? Also, if there is something fundamentally wrong with my structure for this functionality let me know! Thanks!!
UPDATE:
While I would still appreciate input on better possibilities if they exist, this is what I have gotten working now:
class User < ActiveRecord::Base
# stuff...
def updated_threads
MsgThread.find_by_sql("
SELECT msg_threads.* FROM msg_threads
INNER JOIN messages ON messages.msg_thread_id = msg_threads.id
INNER JOIN recipiences ON recipiences.msg_thread_id = msg_threads.id
WHERE (SELECT COUNT(*) FROM `reads` WHERE reads.message_id = messages.id AND reads.user_id = #{self.id}) = 0
AND (SELECT COUNT(*) FROM recipiences WHERE recipiences.user_id = #{self.id} AND recipiences.msg_thread_id = msg_threads.id) > 0
")
end
end
Seems to be working fine!
Also to check if a specific thread (and message) are read:
class Message < ActiveRecord::Base
# stuff...
def read?(user_id)
Read.exists?(:user_id => user_id, :message_id => self.id)
end
end
class MsgThread < ActiveRecord::Base
# stuff...
def updated?(user_id)
updated = false
self.messages.each { |m| updated = true if !m.read?(user_id) }
updated
end
end
Any suggestions to improve this?
Add a named_scope to the MsgThread model:
class MsgThread < ActiveRecord::Base
named_scope :unread_threads, lambda { |user|
{
:include => [{:messages=>[:reads]}, recipiencies],
:conditions => ["recipiences.user_id = ? AND reads.message_id IS NULL",
user.id],
:group => "msg_threads.id"
}}
end
Note: Rails uses LEFT OUTER JOIN for :include. Hence the IS NULL check works.
Now you can do the following:
MsgThread.unread_threads(current_user)
Second part can be written as:
class Message
has_many :reads
def read?(usr)
reads.exists?(:user_id => usr.id)
end
end
class MsgThread < ActiveRecord::Base
def updated?(usr)
messages.first(:joins => :reads,
:conditions => ["reads.user_id = ? ", usr.id]
) != nil
end
end
You might want to take a look at Arel, which can help with complex SQL queries. I believe (don't quote me) this is already baked into Rails3.

Active Record: ordering finds and also returning nulls

I want to find a ordered list of runners by their results.
models
class Race < ActiveRecord::Base
has_many :runners, :dependent => :destroy
end
class Runner < ActiveRecord::Base
belongs_to :race
has_one :result, :dependent => :destroy
end
class Result < ActiveRecord::Base
belongs_to :runner
end
trying to use something like this
ordered_runners = race.runners.all(:include => :result, :order => 'results.position ASC')
position is their finishing position ie [1,2,3,4....]
but if a result is missing (nil) then the runner is not included. Is there a way to do this and return all runners?
cheers
Runners without Results are not included because :include only brings in the data minimizing the number of queries to avoid N+1 hits to the db. You want to do an outer :join to include all runners no matter if they have a result or not.
ordered_runners = race.runners.all(:joins => "left outer join results on runners.id = results.runner_id", :order => 'results.position ASC')
Check this code based on your migration column/table names and your database.
This should return the runners with a null result:
race.runners.all(:include => :result, :conditions => "results IS NULL", :order => 'results.position ASC')

how to access rails join model attributes when using has_many :through

I have a data model something like this:
# columns include collection_item_id, collection_id, item_id, position, etc
class CollectionItem < ActiveRecord::Base
self.primary_key = 'collection_item_id'
belongs_to :collection
belongs_to :item
end
class Item < ActiveRecord::Base
has_many :collection_items
has_many :collections, :through => :collection_items, :source => :collection
end
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position
end
An Item can appear in multiple collections and also more than once in the same collection at different positions.
I'm trying to create a helper method that creates a menu containing every item in every collection. I want to use the collection_item_id to keep track of the currently selected item between requests, but I can't access any attributes of the join model via the Item class.
def helper_method( collection_id )
colls = Collection.find :all
colls.each do |coll|
coll.items.each do |item|
# !!! FAILS HERE ( undefined method `collection_item_id' )
do_something_with( item.collection_item_id )
end
end
end
I tried this as well but it also fails with ( undefined method `collection_item' )
do_something_with( item.collection_item.collection_item_id )
Edit: thanks to serioys sam for pointing out that the above is obviously wrong
I have also tried to access other attributes in the join model, like this:
do_something_with( item.position )
and:
do_something_with( item.collection_item.position )
Edit: thanks to serioys sam for pointing out that the above is obviously wrong
but they also fail.
Can anyone advise me how to proceed with this?
Edit: -------------------->
I found from online documentation that using has_and_belongs_to_many will attach the join table attributes to the retreived items, but apparently it is deprecated. I haven't tried it yet.
Currently I am working on amending my Collection model like this:
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position, :include => :item
...
end
and changing the helper to use coll.collection_items instead of coll.items
Edit: -------------------->
I've changed my helper to work as above and it works fine - (thankyou sam)
It's made a mess of my code - because of other factors not detailed here - but nothing that an hour or two of re-factoring wont sort out.
In your example you have defined in Item model relationship as has_many for collection_items and collections the generated association method is collection_items and collections respectively both of them returns an array so the way you are trying to access here is wrong. this is primarily case of mant to many relationship. just check this Asscociation Documentation for further reference.
do_something_with( item.collection_item_id )
This fails because item does not have a collection_item_id member.
do_something_with( item.collection_item.collection_item_id )
This fails because item does not have a collection_item member.
Remember that the relation between item and collection_items is a has_many. So item has collection_items, not just a single item. Also, each collection has a list of collection items. What you want to do is probably this:
colls = Collection.find :all
colls.each do |coll|
coll.collection_items.each do |collection_item|
do_something_with( collection_item.id )
end
end
A couple of other pieces of advice:
Have you read the documentation for has_many :through in the Rails Guides? It is pretty good.
You shouldn't need the :source parameters in the has_many declarations, since you have named your models and associations in a sensible way.
I found from online documentation that using has_and_belongs_to_many will attach the join table attributes to the retreived items, but apparently it is deprecated. I haven't tried it yet.
I recommend you stick with has_many :through, because has_and_belongs_to_many is more confusing and doesn't offer any real benefits.
I was able to get this working for one of my models:
class Group < ActiveRecord::Base
has_many :users, :through => :memberships, :source => :user do
def with_join
proxy_target.map do |user|
proxy_owner = proxy_owner()
user.metaclass.send(:define_method, :membership) do
memberships.detect {|_| _.group == proxy_owner}
end
user
end
end
end
end
In your case, something like this should work (haven't tested):
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position do
def with_join
proxy_target.map do |items|
proxy_owner = proxy_owner()
item.metaclass.send(:define_method, :join) do
collection_items.detect {|_| _.collection == proxy_owner}
end
item
end
end
end
end
Now you should be able to access the CollectionItem from an Item as long as you access your items like this (items.with_join):
def helper_method( collection_id )
colls = Collection.find :all
colls.each do |coll|
coll.items.with_join.each do |item|
do_something_with( item.join.collection_item_id )
end
end
end
Here is a more general solution that you can use to add this behavior to any has_many :through association:
http://github.com/TylerRick/has_many_through_with_join_model
class Collection < ActiveRecord::Base
has_many :collection_items, :order => :position
has_many :items, :through => :collection_items, :source => :item, :order => :position, :extend => WithJoinModel
end

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