I want to join my named scopes as I generate them with an array.
how wouldI do that , i can't join named scopes, is there a better way to do this?
scope :search, ->(attrs_for_search,params) do
if attrs_for_search.present?
params_to_search_on = params.keys & attrs_for_search
params_to_search_on.collect{|x| where("#{x} ILIKE ?", "%#{params[x]}%") }
else
none
end
end
Contact.search(%w[email],{'email => 'jason'})
I think that you can create a scope and use the 'send' method to join the scopes.
scope :search, ->(field, value) do
where("#{field} LIKE ?", "%#{value}%")
end
def self.multi_search(params)
result = nil
params_to_search_on = params.keys
params_to_search_on.each do |k|
if result.nil?
result = Message.send(:search, k, params[k])
else
result = result.send(:search, k, params[k])
end
end
result
end
Hopes this help you.
You can't chain scopes when you return an array.
You can:
Try returning a relation:
results = params_to_search_on.collect{|x| where("#{x} ILIKE ?", "%#{params[x]}%") }
where(id: results.flatten.map(&:id))
I have not tested this, but I think you will need flatten because results is an array of relations [rel_1,_rel_2]
Then you can use/chain/attach-a-bunch-of scopes like this:
Contact.search(attrs, params).other_scope.another_scope(with_params)
You may want to read about full text search, to expand this topic, I would need to know the DB you are using.
Related
I am currently writing a search method for my rails applications, and at the moment it works fine. I have the following in my game.rb:
def self.search(search)
if search
find(:all, :conditions => ['game_name LIKE ? OR genre LIKE ? OR console LIKE ?', "%#{search}%", "#{search}", "#{search}"])
else
find(:all)
end
end
Now that searches fine, but my problem is that if there is a record in game_name that has the word 'playstation' in it, it will finish the search there. It only returns that record, rather than all games that have 'playstation' stored in console. Now I understand this is because I have 'OR' in my conditions, but I don't know an alternative. 'AND' requires all the conditions to match or none return at all. What is an alternative I can use to AND and OR? Help would be much appreciated.
If there is a solution that has separate search boxes and entries, then that would be fine, I don't necessarily require the search to find it all based on one search form.
If I understand your question correctly, your SQL looks good to me for what you are trying to do. An OR clause will return all records that match in column1, column2, or column3. It doesn't stop at the first match. I do see an issue with your parameters in that the first you are using LIKE with % but in the second two you aren't, maybe that is where your issue is coming from.
Should this be your find (% around second and third search)?
find(:all, :conditions => ['game_name LIKE ? OR genre LIKE ? OR console LIKE ?', "%#{search}%", "%#{search}%", "%#{search}%"])
or better use DRY version (above will not work for Rails 4.2+):
Item.where('game_name LIKE :search OR genre LIKE :search OR console LIKE :search', search: "%#{search}%")
What if you have 15 columns to search then you will repeat key 15 times. Instead of repeating key 15 times in query you can write like this:
key = "%#{search}%"
#items = Item.where('game_name LIKE :search OR genre LIKE :search OR console LIKE :search', search: key).order(:name)
It will give you same result.
Thanks
I think this is a little bit of a cleaner solution. This allows you to add/remove columns more easily.
key = "%#{search}%"
columns = %w{game_name genre console}
#items = Item.where(
columns
.map {|c| "#{c} like :search" }
.join(' OR '),
search: key
)
A more generic solution for searching in all fields of the model would be like this
def search_in_all_fields model, text
model.where(
model.column_names
.map {|field| "#{field} like '%#{text}%'" }
.join(" or ")
)
end
Or better as a scope in the model itself
class Model < ActiveRecord::Base
scope :search_in_all_fields, ->(text){
where(
column_names
.map {|field| "#{field} like '%#{text}%'" }
.join(" or ")
)
}
end
You would just need to call it like this
Model.search_in_all_fields "test"
Before you start.., no, sql injection would probably not work here but still better and shorter
class Model < ActiveRecord::Base
scope :search_all_fields, ->(text){
where("#{column_names.join(' || ')} like ?", "%#{text}%")
}
end
I think this is a more efficient solution if you want to search an array of columns as I do.
First and most importantly you can add a private function to your model that creates a query template:
def self.multiple_columns_like_query(array)
array.reduce('') { |memo, x| #
unless memo == '' #
memo += ' or ' # This is the
end #
memo += "#{x} like :q" # core part
} #
end
Than you can use the function in your search function:
def self.search(query)
if fields = self.searched_fields && query
where multiple_like_query(fields), q: "%#{query}%"
end
end
Here you should also define self.searched_fields as an array of field names.
I've written a couple of complex queries (at least to me) with Ruby on Rail's query interface:
watched_news_posts = Post.joins(:news => :watched).where(:watched => {:user_id => id})
watched_topic_posts = Post.joins(:post_topic_relationships => {:topic => :watched}).where(:watched => {:user_id => id})
Both of these queries work fine by themselves. Both return Post objects. I would like to combine these posts into a single ActiveRelation. Since there could be hundreds of thousands of posts at some point, this needs to be done at the database level. If it were a MySQL query, I could simply user the UNION operator. Does anybody know if I can do something similar with RoR's query interface?
Here's a quick little module I wrote that allows you to UNION multiple scopes. It also returns the results as an instance of ActiveRecord::Relation.
module ActiveRecord::UnionScope
def self.included(base)
base.send :extend, ClassMethods
end
module ClassMethods
def union_scope(*scopes)
id_column = "#{table_name}.id"
sub_query = scopes.map { |s| s.select(id_column).to_sql }.join(" UNION ")
where "#{id_column} IN (#{sub_query})"
end
end
end
Here's the gist: https://gist.github.com/tlowrimore/5162327
Edit:
As requested, here's an example of how UnionScope works:
class Property < ActiveRecord::Base
include ActiveRecord::UnionScope
# some silly, contrived scopes
scope :active_nearby, -> { where(active: true).where('distance <= 25') }
scope :inactive_distant, -> { where(active: false).where('distance >= 200') }
# A union of the aforementioned scopes
scope :active_near_and_inactive_distant, -> { union_scope(active_nearby, inactive_distant) }
end
I also have encountered this problem, and now my go-to strategy is to generate SQL (by hand or using to_sql on an existing scope) and then stick it in the from clause. I can't guarantee it's any more efficient than your accepted method, but it's relatively easy on the eyes and gives you a normal ARel object back.
watched_news_posts = Post.joins(:news => :watched).where(:watched => {:user_id => id})
watched_topic_posts = Post.joins(:post_topic_relationships => {:topic => :watched}).where(:watched => {:user_id => id})
Post.from("(#{watched_news_posts.to_sql} UNION #{watched_topic_posts.to_sql}) AS posts")
You can do this with two different models as well, but you need to make sure they both "look the same" inside the UNION -- you can use select on both queries to make sure they will produce the same columns.
topics = Topic.select('user_id AS author_id, description AS body, created_at')
comments = Comment.select('author_id, body, created_at')
Comment.from("(#{comments.to_sql} UNION #{topics.to_sql}) AS comments")
Based on Olives' answer, I did come up with another solution to this problem. It feels a little bit like a hack, but it returns an instance of ActiveRelation, which is what I was after in the first place.
Post.where('posts.id IN
(
SELECT post_topic_relationships.post_id FROM post_topic_relationships
INNER JOIN "watched" ON "watched"."watched_item_id" = "post_topic_relationships"."topic_id" AND "watched"."watched_item_type" = "Topic" WHERE "watched"."user_id" = ?
)
OR posts.id IN
(
SELECT "posts"."id" FROM "posts" INNER JOIN "news" ON "news"."id" = "posts"."news_id"
INNER JOIN "watched" ON "watched"."watched_item_id" = "news"."id" AND "watched"."watched_item_type" = "News" WHERE "watched"."user_id" = ?
)', id, id)
I'd still appreciate it if anybody has any suggestions to optimize this or improve the performance, because it's essentially executing three queries and feels a little redundant.
You could also use Brian Hempel's active_record_union gem that extends ActiveRecord with an union method for scopes.
Your query would be like this:
Post.joins(:news => :watched).
where(:watched => {:user_id => id}).
union(Post.joins(:post_topic_relationships => {:topic => :watched}
.where(:watched => {:user_id => id}))
Hopefully this will be eventually merged into ActiveRecord some day.
Could you use an OR instead of a UNION?
Then you could do something like:
Post.joins(:news => :watched, :post_topic_relationships => {:topic => :watched})
.where("watched.user_id = :id OR topic_watched.user_id = :id", :id => id)
(Since you are joins the watched table twice I'm not too sure what the names of the tables will be for the query)
Since there are a lot of joins, it might also be quite heavy on the database, but it might be able to be optimized.
How about...
def union(scope1, scope2)
ids = scope1.pluck(:id) + scope2.pluck(:id)
where(id: ids.uniq)
end
Arguably, this improves readability, but not necessarily performance:
def my_posts
Post.where <<-SQL, self.id, self.id
posts.id IN
(SELECT post_topic_relationships.post_id FROM post_topic_relationships
INNER JOIN watched ON watched.watched_item_id = post_topic_relationships.topic_id
AND watched.watched_item_type = "Topic"
AND watched.user_id = ?
UNION
SELECT posts.id FROM posts
INNER JOIN news ON news.id = posts.news_id
INNER JOIN watched ON watched.watched_item_id = news.id
AND watched.watched_item_type = "News"
AND watched.user_id = ?)
SQL
end
This method returns an ActiveRecord::Relation, so you could call it like this:
my_posts.order("watched_item_type, post.id DESC")
There is an active_record_union gem.
Might be helpful
https://github.com/brianhempel/active_record_union
With ActiveRecordUnion, we can do:
the current user's (draft) posts and all published posts from anyone
current_user.posts.union(Post.published)
Which is equivalent to the following SQL:
SELECT "posts".* FROM (
SELECT "posts".* FROM "posts" WHERE "posts"."user_id" = 1
UNION
SELECT "posts".* FROM "posts" WHERE (published_at < '2014-07-19 16:04:21.918366')
) posts
In a similar case I summed two arrays and used Kaminari:paginate_array(). Very nice and working solution. I was unable to use where(), because I need to sum two results with different order() on the same table.
Heres how I joined SQL queries using UNION on my own ruby on rails application.
You can use the below as inspiration on your own code.
class Preference < ApplicationRecord
scope :for, ->(object) { where(preferenceable: object) }
end
Below is the UNION where i joined the scopes together.
def zone_preferences
zone = Zone.find params[:zone_id]
zone_sql = Preference.for(zone).to_sql
region_sql = Preference.for(zone.region).to_sql
operator_sql = Preference.for(Operator.current).to_sql
Preference.from("(#{zone_sql} UNION #{region_sql} UNION #{operator_sql}) AS preferences")
end
Less problems and easier to follow:
def union_scope(*scopes)
scopes[1..-1].inject(where(id: scopes.first)) { |all, scope| all.or(where(id: scope)) }
end
So in the end:
union_scope(watched_news_posts, watched_topic_posts)
gem 'active_record_extended'
Also has a set of union helpers among many others.
I would just run the two queries you need and combine the arrays of records that are returned:
#posts = watched_news_posts + watched_topics_posts
Or, at the least test it out. Do you think the array combination in ruby will be far too slow? Looking at the suggested queries to get around the problem, I'm not convinced that there will be that significant of a performance difference.
Elliot Nelson answered good, except the case where some of the relations are empty. I would do something like that:
def union_2_relations(relation1,relation2)
sql = ""
if relation1.any? && relation2.any?
sql = "(#{relation1.to_sql}) UNION (#{relation2.to_sql}) as #{relation1.klass.table_name}"
elsif relation1.any?
sql = relation1.to_sql
elsif relation2.any?
sql = relation2.to_sql
end
relation1.klass.from(sql)
end
When we add UNION to the scopes, it breaks at time due to order_by clause added before the UNION.
So I changed it in a way to give it a UNION effect.
module UnionScope
def self.included(base)
base.send(:extend, ClassMethods)
end
module ClassMethods
def union_scope(*scopes)
id_column = "#{table_name}.id"
sub_query = scopes.map { |s| s.pluck(:id) }.flatten
where("#{id_column} IN (?)", sub_query)
end
end
end
And then use it like this in any model
class Model
include UnionScope
scope :union_of_scopeA_scopeB, -> { union_scope(scopeA, scopeB) }
end
Tim's answer is great. It uses the ids of the scopes in the WHERE clause. As shosti reports, this method is problematic in terms of performance because all ids need to be generated during query execution. This is why, I prefer joeyk16 answer. Here a generalized module:
module ActiveRecord::UnionScope
def self.included(base)
base.send :extend, ClassMethods
end
module ClassMethods
def self.union(*scopes)
self.from("(#{scopes.map(&:to_sql).join(' UNION ')}) AS #{self.table_name}")
end
end
end
If you don't want to use SQL syntax inside your code, here's solution with arel
watched_news_posts = Post.joins(:news => :watched).where(:watched => {:user_id => id}).arel
watched_topic_posts = Post.joins(:post_topic_relationships => {:topic => :watched}).where(:watched => {:user_id => id}).arel
results = Arel::Nodes::Union.new(watched_news_posts, watched_topic_posts)
from(Post.arel_table.create_table_alias(results, :posts))
I feel this should be very simple but my brain is short-circuiting on it. If I have an object representing the current user, and want to query for all users except the current user, how can I do this, taking into account that the current user can sometimes be nil?
This is what I am doing right now:
def index
#users = User.all
#users.delete current_user
end
What I don't like is that I am doing post-processing on the query result. Besides feeling a little wrong, I don't think this will work nicely if I convert the query over to be run with will_paginate. Any suggestions for how to do this with a query? Thanks.
It is possible to do the following in Rails 4 and up:
User.where.not(id: id)
You can wrap it in a nice scope.
scope :all_except, ->(user) { where.not(id: user) }
#users = User.all_except(current_user)
Or use a class method if you prefer:
def self.all_except(user)
where.not(id: user)
end
Both methods will return an AR relation object. This means you can chain method calls:
#users = User.all_except(current_user).paginate
You can exclude any number of users because where() also accepts an array.
#users = User.all_except([1,2,3])
For example:
#users = User.all_except(User.unverified)
And even through other associations:
class Post < ActiveRecord::Base
has_many :comments
has_many :commenters, -> { uniq }, through: :comments
end
#commenters = #post.commenters.all_except(#post.author)
See where.not() in the API Docs.
#users = (current_user.blank? ? User.all : User.find(:all, :conditions => ["id != ?", current_user.id]))
You can also create named_scope, e.g. in your model:
named_scope :without_user, lambda{|user| user ? {:conditions => ["id != ?", user.id]} : {} }
and in controller:
def index
#users = User.without_user(current_user).paginate
end
This scope will return all users when called with nil and all users except given in param in other case. The advantage of this solution is that you are free to chain this call with other named scopes or will_paginate paginate method.
Here is a shorter version:
User.all :conditions => (current_user ? ["id != ?", current_user.id] : [])
One note on GhandaL's answer - at least in Rails 3, it's worth modifying to
scope :without_user, lambda{|user| user ? {:conditions => ["users.id != ?", user.id]} : {} }
(the primary change here is from 'id != ...' to 'users.id !=...'; also scope instead of named_scope for Rails 3)
The original version works fine when simply scoping the Users table. When applying the scope to an association (e.g. team.members.without_user(current_user).... ), this change was required to clarify which table we're using for the id comparison. I saw a SQL error (using SQLite) without it.
Apologies for the separate answer...i don't yet have the reputation to comment directly on GhandaL's answer.
Very easy solution I used
#users = User.all.where("id != ?", current_user.id)
User.all.where("id NOT IN(?)", current_user.id) will through exception
undefined method where for #<Array:0x0000000aef08f8>
User.where("id NOT IN (?)", current_user.id)
Another easy way you could do it:
#users = User.all.where("id NOT IN(?)", current_user.id)
an array would be more helpful
arrayID[0]=1
arrayID[1]=3
User.where.not(id: arrayID)
User.where(:id.ne=> current_user.id)
ActiveRecord::QueryMethods#excluding (Rails 7+)
Starting from Rails 7, there is a new method ActiveRecord::QueryMethods#excluding.
A quote right from the official Rails docs:
excluding(*records)
Excludes the specified record (or collection of records) from the resulting relation. For example:
Post.excluding(post)
# SELECT "posts".* FROM "posts" WHERE "posts"."id" != 1
Post.excluding(post_one, post_two)
# SELECT "posts".* FROM "posts" WHERE "posts"."id" NOT IN (1, 2)
This can also be called on associations. As with the above example, either a single record of collection thereof may be specified:
post = Post.find(1)
comment = Comment.find(2)
post.comments.excluding(comment)
# SELECT "comments".* FROM "comments" WHERE "comments"."post_id" = 1 AND "comments"."id" != 2
This is short-hand for .where.not(id: post.id) and .where.not(id: [post_one.id, post_two.id]).
An ArgumentError will be raised if either no records are specified, or if any of the records in the collection (if a collection is passed in) are not instances of the same model that the relation is scoping.
Also aliased as: without
Sources:
Official docs - ActiveRecord::QueryMethods#excluding
PR - Add #excluding to ActiveRecord::Relation to exclude a record (or collection of records) from the resulting relation.
What's Cooking in Rails 7?
What you are doing is deleting the current_user from the #users Array. This won't work since there isn't a delete method for arrays. What you probably want to do is this
def index
#users = User.all
#users - [current_user]
end
This will return a copy of the #users array, but with the current_user object removed (it it was contained in the array in the first place.
Note: This may not work if array subtraction is based on exact matches of objects and not the content. But it worked with strings when I tried it. Remember to enclose current_user in [] to force it into an Array.
named_scope :incomplete?, lambda { |user_id, todo_id|
{ :select => 1, :conditions =>
[ "#{user_id} not in (select user_todos.user_id from user_todos) and
#{todo_id} not in (select user_todos.todo_id from user_todos)" ]
}
}
I'm getting a nil result. I want it to return true. What I gotta do!?
Also, is there a better way to write this?
There's a huge issue with your code: named scopes are not intended to return booleans or single values, are intended to returns filters to be chained.
Use a class method instead. Also, use interpolation, don't write values directly into the SQL code.
class YourModel
def self.incomplete?(user_id, todo_id)
exists?(["? not in (select user_todos.user_id from user_todos) and ? not in (select user_todos.todo_id from user_todos)", user_id, todo_id])
end
end
Thx. I discovered the issues! I ended up writing this:
def incomplete?(user_id, todo_id)
return UserTodo.find_by_sql("select case when (#{user_id} not in (select user_id from user_todos)) and
(#{todo_id} not in (select todo_id from user_todos)) then true else false end as incomplete from user_todos")
end
But I like your approach better.
I have a user model and a cd model connected through a join table 'cds_users'. I'm trying to return a hash of users plus each cd they have in common with the original user.
#user.users_with_similar_cds(1,4,5)
# => {:bob => [4], :tim => [1,5]}
Is there a better/faster way of doing this without looping so much? Maybe a more direct way?
def users_with_similar_cds(*args)
similar_users = {}
Cd.find(:all, :conditions => ["cds.id IN (?)", args]).each do |cd|
cd.users.find(:all, :conditions => ["users.id != ?", self.id]).each do |user|
if similar_users[user.name]
similar_users[user.name] << cd.id
else
similar_users[user.name] = [cd.id]
end
end
end
similar_users
end
[addition]
Taking the join model idea, I could do something like this. I'll call the model 'joined'.
def users_with_similar_cds(*args)
similar_users = {}
Joined.find(:all, :conditions => ["user_id != ? AND cd_id IN (?)", self.id, args]).each do |joined|
if similar_users[joined.user_id]
similar_users[joined.user_id] << cd_id
else
similar_users[joined.user_id] = [cd_id]
end
end
similar_users
end
Would this be the fastest way on large data sets?
You could use find_by_sql on the Users model, and Active Record will dynamically add methods for any extra fields returned by the query. For example:
similar_cds = Hash.new
peeps = Users.find_by_sql("SELECT Users.*, group_concat(Cds_Users.cd_id) as cd_ids FROM Users, Cds_Users GROUP BY Users.id")
peeps.each { |p| similar_cds[p.name] = p.cd_ids.split(',') }
I haven't tested this code, and this particular query will only work if your database supports group_concat (eg, MySQL, recent versions of Oracle, etc), but you should be able to do something similar with whatever database you use.
Yap, you can, with only 2 selects:
Make a join table model named CdUser (use has_many.. through)
# first select
cd_users = CdUser.find(:all, :conditions => ["cd_id IN (?)", args])
cd_users_by_cd_id = cd_users.group_by{|cd_user| cd_user.cd_id }
users_ids = cd_users.collect{|cd_user| cd_user.user_id }.uniq
#second select
users_by_id = User.find_all_by_id(users_ids).group_by{|user| user.id}
cd_users_by_cd_id.each{|cd_id, cd_user_hash|
result_hash[:cd_id] = cd_users_hash.collect{|cd_user| users_by_id[cd_user.user_id]}
}
This is just an ideea, haven't tested :)
FYI: http://railscasts.com/episodes/47-two-many-to-many