So I have 2 models: City and Country. City belongs_to Country, you know how it works.
How to find Country when I'm putting City name into search field?
I know how it works with 1 model
#countries = Country.where(["name LIKE ?", "%#{params[:search]}%"])
but what to do in this case?
I'll be grateful for any useful links or tips, cos I can't find something like that.
Try this:
#countries = Country.joins(:cities).where("cities.name LIKE ?", "%#{params[:search]}%")
This may be what you're looking for:
#countries = Country.all.includes(:cities).where("cities.name" => params[:search]).all
By the way, it is a bad idea to put search form entry directly into an SQL query as written in your original post as it opens your app up to SQL injection. Read this article here under the header "A1 SQL Injection":
https://blog.codeship.com/preproduction-checklist-for-a-rails-app/
Related
I have the following ActiveRecord Models
class Publication < ActiveRecord::Base
attr_accessible :id, :pname
has_many :advertisements
end
class Vendor < ActiveRecord::Base
attr_accessible :id, :vname
has_many :advertisements
end
class Advertisement < ActiveRecord::Base
attr_accessible :id, :vendor_id, :publication_id, :prose, :aname
belongs_to :vendor
belongs_to :publication
end
The tables for these have the same fields as their accessible attributes.
I would like to be able to sort on the publication name, ad name, or vendor name, ascending or descending.
I also have a controller for the advertisements, where I want to display a list of ads. The list displays the name of the ad (aname), prose of the ad (prose), the name of the vendor (vname), and the name of the publication (pname).
The SQL query for ordering by publication name would look something like:
SELECT ads.aname AS aname, ads.id, ads.prose, ven.vname AS vname, pub.pname AS pname
FROM advertisements AS ads
INNER JOIN publications AS pub ON ads.publication_id = pub.id
INNER JOIN vendors AS ven ON ads.vendor_id = ven.id
ORDER BY <sort_column> <sort_order>
Where sort_column could be one of "pname", "aname", or "vname", and sort_order could be one of "ASC" or "DESC", and both would come as parameters from the web form along with the pagination page number.
The controller index code looks like this:
class AdvertisementsController < ApplicationController
def index
sort_column = params[:sort_column]
sort_order = params[:sort_order]
#ads = Advertisement.join( somehow join tables)
.where(some condition).where(some other condition)
.order("#{sort_column} #{sort_order}") ### I don't know what to do here
.paginate(page: params[:page], per_page: 10) #from will_paginate
end
# other controller methods.......
end
The index view table snippet (written in SLIM) looks like this:
tr
- #ads.each do |ad|
td = ad.id
td = ad.aname
td = ad.pname
td = ad.vname
I am aware that I could use AREL to do this, but I have been mucking around with AREL in the Rails console trying to generate and execute this query with pagination, and reading tutorials on the web and I can't figure out how to get this query in AREL, with sorting on joined fields, and with the ability to use a will_paginate Ruby query clause to paginate the query.
How does one use AREL, or even ActiveRecord to do this? I appreciate any help I can get.
You can accomplish what you want with vanilla ActiveRecord methods, without Arel. What you have is pretty close, this might help you get there.
# whitelist incoming params
sort_column = %w(pname aname vname).include?(params[:sort_column]) ? params[:sort_column] : "pname"
sort_order = %w(asc desc).include?(params[:sort_order]) ? params[:sort_order] : "desc"
#ads = Advertisement.select("advertisements.*, vendors.vname, publications.pname").
joins(:publication, :vendor).
where(some condition).
where(some other condition).
order("#{sort_column} #{sort_order}").
page(params[:page]).per_page(10)
You can have the solution work with both Arel and ActiveRecord. I would suggest you stick to ActiveRecord as much as you can unless you cant do it with AR.
Arel is great, but lately I have seen that in my code base, it reduces overall readability, esp if you mix it with AR or use too much of it.
Also couple of other suggestions:
On the same query about try using "includes" instead of using "joins". You might that its easier than having to add the select clause. I use includes for outerjoins, but for a more detailed comparison, google "includes vs joins", it is very interesting.
In complete opposite direction of my first suggestion, in case you queries are going to get complex, I highly recommend using https://github.com/activerecord-hackery/ransack or https://github.com/activerecord-hackery/squeel for your use case.
Especially if you not doing the above for just learning purposes.
I'm working on a Rails 3.2 app that uses Datamapper as its ORM. I'm looking for a way to sort a result set by an attribute of the associated model. Specifically I have the following models:
class Vehicle
include DataMapper::Resource
belongs_to :user
end
class User
include DataMapper::Resource
has n, :vehicles
end
Now I want to be able to query the vehicles and sort them by the name of the driver. I tried the following but neither seems to work with Datamapper:
> Vehicle.all( :order => 'users.name' )
ArgumentError: +options[:order]+ entry "users.name" does not map to a property in Vehicle
> Vehicle.all( :order => { :users => 'name' } )
ArgumentError: +options[:order]+ entry [:users, "name"] of an unsupported object Array
Right now I'm using Ruby to sort the result set post-query but obviously that's not helping performance any, also it stops me from further chaining on other scopes.
I spent some more time digging around and finally turned up an old blog which has a solution to this problem. It involves manually building the ordering query in DataMapper.
From: http://rhnh.net/2010/12/01/ordering-by-a-field-in-a-join-model-with-datamapper
def self.ordered_by_vehicle_name direction = :asc
order = DataMapper::Query::Direction.new(vehicle.name, direction)
query = all.query
query.instance_variable_set("#order", [order])
query.instance_variable_set("#links", [relationships['vehicle'].inverse])
all(query)
end
This will let you order by association and still chain on other scopes, e.g.:
User.ordered_by_vehicle_name(:desc).all( :name => 'foo' )
It's a bit hacky but it does what I wanted it to do at least ;)
Note: I'm not familiar with DataMapper and my answer might not be within the standards and recommendations of using DataMapper, but it should hopefully give you the result you're looking for.
I've been looking through various Google searches and the DataMapper documentation and I haven't found a way to "order by assocation attribute". The only solution I have thought of is "raw" SQL.
The query would look like this.
SELECT vehicles.* FROM vehicles
LEFT JOIN users ON vehicles.user_id = users.id
ORDER BY users.name
Unfortunately, from my understanding, when you directly query the database you won't get the Vehicle object, but the data from the database.
From the documentation: http://datamapper.org/docs/find.html. It's near the bottom titled "Talking directly to your data-store"
Note that this will not return Zoo objects, rather the raw data straight from the database
Vehicle.joins(:user).order('users.name').all
or in Rails 2.3,
Vehicle.all(:joins => "inner join users on vehicles.user_id = user.id", :order => 'users.name')
I want to build a rails request with 2 models.
I think it's quite simple, but I don't want to do a loop myself.
I'm in my country model:
def self.find_for_user(user_id)
wines = Wine.where("user_id = ?", user_id).group(:country_id)
where("countries.id IN ?", wines.map())
end
I want to get all countries depending the first request (the wines grouped by countries, I just need the countries)
I think I can do this in a single line where I put map() or another instruction. I just need to get all country_id fields for wines.
Thanks.
Assuming that you've got an association set up between wines and country (ie. has_many :wines in country.rb), I think this is what you're looking for:
def self.find_for_user(user_id)
joins(:wines).where('wines.user_id = ?', user_id).uniq
end
If all you want is all countries that have wine for a specific user, you can do that in SQL:
where("countries.id in (select country_id from wines where wines.user_id = ?)", user_id)
I'll explain this as best as possible. I have a query on user posts:
#selected_posts = Posts.where(:category => "Baseball")
I would like to write the following statement. Here it is in pseudo terms:
User.where(user has a post in #selected_posts)
Keep in mind that I have a many to many relationship setup so post.user is usable.
Any ideas?
/EDIT
#posts_matches = User.includes(#selected_posts).map{ |user|
[user.company_name, user.posts.count, user.username]
}.sort
Basically, I need the above to work so that it uses the users that HAVE posts in selected_posts and not EVERY user we have in our database.
Try this:
user.posts.where("posts.category = ?", "Baseball")
Edit 1:
user.posts.where("posts.id IN (?)", #selected_posts)
Edit 2:
User.select("users.company_name, count(posts.id) userpost_count, user.username").
joins(:posts).
where("posts.id IN (?)", #selected_posts).
order("users.company_name, userpost_count, user.username")
Just use the following:
User.find(#selected_posts.map(&:user_id).uniq)
This takes the user ids from all the selected posts, turns them into an array, and removes any duplicates. Passing an array to user will just find all the users with matching ids. Problem solved.
To combine this with what you showed in your question, you could write:
#posts_matches = User.find(#selected_posts.map(&:user_id).uniq).map{ |user|
[user.company_name, user.posts.size, user.username]
}
Use size to count a relation instead of count because Rails caches the size method and automatically won't look it up more than once. This is better for performance.
Not sure what you were trying to accomplish with Array#sort at the end of your query, but you could always do something like:
#users_with_posts_in_selected = User.find(#selected_posts.map(&:user_id).uniq).order('username DESC')
I don't understand your question but you can pass an array to the where method like this:
where(:id => #selected_posts.map(&:id))
and it will create a SQL query like WHERE id IN (1,2,3,4)
By virtue of your associations your selected posts already have the users:
#selected_posts = Posts.where("posts.category =?", "Baseball")
#users = #selected_posts.collect(&:user);
You'll probably want to remove duplicate users from #users.
I am currently using scopes in my model to perform searches within a database. I can stack these scopes and it will output results matching all parameters.
scope :search_between, lambda{|begin_date, end_date|
where "sub.date BETWEEN ? AND ?", begin_date, end_date
}
What I am having trouble with is integrating a keywords search that will search the entire database and output the results that contain the sum of the keywords. I would like to do something like this (displayed for simplicity):
scope :keywords, lambda{|search|
search.chomp.split(/,\s*/) do |item|
where "date like ? or city like ? or state like ?", "%#{item}%" and
where "date like ? or city like ? or state like ?", "%#{item}%" and
where "date like ? or city like ? or state like ?", "%#{item}%"
end
}
I am currently using something like this to take care of searching multiple columns:
scope :keywords, lambda{|search|
search.chomp.split(/,\s*/) do |item|
where(Sub.column_names.map {|cn| "#{cn} like ?" }.join("or "), "%#{item}%"] Sub.column_names.size)).join(' AND ')
end
}
My problem is that I want to do multiple "where()'s" in the scope. Is it possible and if so, how?
Just turn it into a method that returns a scope:def self.keywords(search)
scope = self.scoped
search.chomp.split(/,\s*/).each do |item|
scope = scope.where(["date like ? or
city like ? or
state like ?", "%#{item}%","%#{item}%","%#{item}%"])
end
scope
end
The drawback is that you can't chain keywords off of other scopes, but you can chain other scopes off of keywords.
I think you will be hitting the limit with using the database for full text search.
Have you looked into using Solr or Sphinx for your full text searches? There's also IndexTank if you want to use a 3rd party service.
For solr, there are rubygems available to help you: sunspot, solrsan(i'm the author)
Sunspot is definitely more full-featured and solrsan is a barebones layer.