Rails 2.3.5
I've looked at a number of other questions relating to building conditions dynamically for an ActiveRecord find.
I'm aware there are some great gems out there like search logic and that this is better in Rails3. However, I'm using geokit for geospacial search and I'm trying to build just a standard conditions set that will allow me to combine a slew of different filters.
I have 12 different filters that I'm trying to combine dynamically for an advanced search. I need to be able to mix equality, greater than, less than, in (?) and IS NULLs conditions.
Here's an example of what I'm trying to get working:
conditions = []
conditions << ["sites.site_type in (?)", params[:site_categories]] if params[:site_categories]
conditions << [<< ["sites.operational_status = ?", 'operational'] if params[:oponly] == 1
condition_set = [conditions.map{|c| c[0] }.join(" AND "), *conditions.map{|c| c[1..-1] }.flatten]
#sites = Site.find :all,
:origin => [lat,lng],
:units => distance_unit,
:limit => limit,
:within => range,
:include => [:chargers, :site_reports, :networks],
:conditions => condition_set,
:order => 'distance asc'
I seem to be able to get this working fine when there are only single variables for the conditions expression but when I have something that is a (?) and has an array of values I'm getting an error for the wrong number of bind conditions. The way I'm joining and flattening the conditions (based on the answer from Combine arrays of conditions in Rails) seems not to handle an array properly and I don't understand the flattening logic enough to track down the issue.
So let's say I have 3 values in params[:site_categories] I'll the above code leaves me with the following:
Conditions is
[["sites.operational_status = ?", "operational"], ["sites.site_type in (?)", ["shopping", "food", "lodging"]]]
The flattened attempt is:
["sites.operational_status = ? AND sites.site_type in (?)", ["operational"], [["shopping", "food", "lodging"]]]
Which gives me:
wrong number of bind variables (4 for 2)
I'm going to step back and work on converting all of this to named scopes but I'd really like to understand how to get this working this way.
Rails 4
users = User.all
users = User.where(id: params[id]) if params[id].present?
users = User.where(state: states) if states.present?
users.each do |u|
puts u.name
end
Old answer
Monkey patch the Array class. Create a file called monkey_patch.rb in config/initializers directory.
class Array
def where(*args)
sql = args.first
unless (sql.is_a?(String) and sql.present?)
return self
end
self[0] = self.first.present? ? " #{self.first} AND #{sql} " : sql
self.concat(args[1..-1])
end
end
Now you can do this:
cond = []
cond.where("id = ?", params[id]) if params[id].present?
cond.where("state IN (?)", states) unless states.empty?
User.all(:conditions => cond)
Related
Basically, I have an app with a tagging system and when someone searches for tag 'badger', I want it to return records tagged "badger", "Badger" and "Badgers".
With a single tag I can do this to get the records:
#notes = Tag.find_by_name(params[:tag_name]).notes.order("created_at DESC")
and it works fine. However if I get multiple tags (this is just for upper and lower case - I haven't figured out the 's' bit either yet):
Tag.find(:all, :conditions => [ "lower(name) = ?", 'badger'])
I can't use .notes.order("created_at DESC") because there are multiple results.
So, the question is.... 1) Am I going about this the right way? 2) If so, how do I get all my records back in order?
Any help much appreciated!
One implementation would be to do:
#notes = []
Tag.find(:all, :conditions => [ "lower(name) = ?", 'badger']).each do |tag|
#notes << tag.notes
end
#notes.sort_by {|note| note.created_at}
However you should be aware that this is what is known as an N + 1 query, in that it makes one query in the outer section, and then one query per result. This can be optimized by changing the first query to be:
Tag.find(:all, :conditions => [ "lower(name) = ?", 'badger'], :includes => :notes).each do |tag|
If you are using Rails 3 or above, it can be re-written slightly:
Tag.where("lower(name) = ?", "badger").includes(:notes) do |tag|
Edited
First, get an array of all possible tag names, plural, singular, lower, and upper
tag_name = params[:tag_name].to_s.downcase
possible_tag_names = [tag_name, tag_name.pluralize, tag_name.singularize].uniq
# It's probably faster to search for both lower and capitalized tags than to use the db's `lower` function
possible_tag_names += possible_tag_names.map(&:capitalize)
Are you using a tagging library? I know that some provide a method for querying multiple tags. If you aren't using one of those, you'll need to do some manual SQL joins in your query (assuming you're using a relational db like MySQL, Postgres or SQLite). I'd be happy to assist with that, but I don't know your schema.
After quite a bit of searching, I'm still a bit lost. There are a few other similar questions out there that deal with paginating multiple models, but they are either unanswered or they pagainate each model separately.
I need to paginate all records of an Account at once.
class Account
:has_many :emails
:has_many :tasks
:has_many :notes
end
So, I'd like to find the 30 most recent "things" no matter what they are. Is this even possible with the current pagination solutions out there?
Like using some combination of eager loading and Kaminari or will_paginate?
Or, should I first set up a polymorphic join of all these things, called Items. Then paginate the most recent 30 items, then do a lookup of the associated records of those items.
And if so, I'm not really sure what that code should look like. Any suggestions?
Which way is better? (or even possible)
Rails 3.1, Ruby 1.9.2, app not in production.
with will_paginate :
#records = #do your work and fetch array of records you want to paginate ( various types )
then do the following :
current_page = params[:page] || 1
per_page = 10
#records = WillPaginate::Collection.create(current_page, per_page, records.size) do |pager|
pager.replace(#records)
end
then in your view :
<%=will_paginate #records%>
Good question... I'm not sure of a "good" solution, but you could do a hacky one in ruby:
You'd need to first fetch out the 30 latest of each type of "thing", and put them into an array, indexed by created_at, then sort that array by created_at and take the top 30.
A totally non-refactored start might be something like:
emails = Account.emails.all(:limit => 30, :order => :created_at)
tasks = Account.tasks.all(:limit => 30, :order => :created_at)
notes = Account.notes.all(:limit => 30, :order => :created_at)
thing_array = (emails + tasks + notes).map {|thing| [thing.created_at, thing] }
# sort by the first item of each array (== the date)
thing_array_sorted = thing_array.sort_by {|a,b| a[0] <=> b[0] }
# then just grab the top thirty
things_to_show = thing_array_sorted.slice(0,30)
Note: not tested, could be full of bugs... ;)
emails = account.emails
tasks = account.tasks
notes = account.notes
#records = [emails + tasks + notes].flatten.sort_by(&:updated_at).reverse
#records = WillPaginate::Collection.create(params[:page] || 1, 30, #records.size) do |pager|
pager.replace(#records)
end
Thats it... :)
I have a method that selects 5 random users who are following a certain user, and adds them to an array.
Relationship.find_all_by_followee_id( user.id ).shuffle[0,4].each do |follower|
follower = User.find(follower.user_id)
array.push follower
end
return array
I'm wondering, is this an efficient way of accomplishing this? My main concern is with the find_all_by_followee_id call. This returns a list of all the relationships where the specified user is being followed (this could be in the 100,000s). And then I shuffle that entire list, and then I trim it to the first 5. Is there a more efficient way to do this?
You can try this:
Relationship.find_all_by_followee_id( user.id, :order => 'rand()', :limit => 5 ) do |follower|
follower = User.find(follower.user_id)
array.push follower
end
return array
Btw, this will work with MySql. If you are using PostgreSQL or anything else you may need to change the rand() with any valid random function that your DB supports.
Some minor changes to make it a little more clean:
return Relationship.find_all_by_followee_id( user.id, :order => 'rand()', :limit => 5 ).collect {|follower| User.find(follower.user_id) }
You can also use a join in there in order to prevent the 5 selects but it won't make much difference.
Edit1:
As #mike.surowiec mentioned.
"Just for everyones benefit, translating this to the non-deprecated active record query syntax looks like this:"
Relationship.where(:followee_id => user.id).order( "random()" ).limit( 5 ).collect {|follower| User.find(follower.user_id) }
I come across a small issue in my app. I'm currently using geokit to find objects near a given location, and I use the sort_by_distance_from on the found set.
See below:
#find = Item.find(:all, :origin =>[self.geocode.lat.to_f,self.geocode.lng.to_f], :within=>50, :include=>[:programs], :conditions=>["programs.name = ?", self.name])
#find.sort_by_distance_from([self.geocode.lat.to_f,self.geocode.lng.to_f]
Is there any way with geokit to paginate form the DB when sorting by distance?
AKA, not calling the full found set?
The distance column isn't working anymore:
"In the current version of geokit-rails, it is not possible to add a where clause using the distance column. I've tried many different ways to do this and didn't get it working."
It behaves the same way for where and order clauses.
One would expect to build a query like this :
scoped = Location.geo_scope(:origin => #somewhere)
scoped = scoped.where('distance <= 5')
results = scoped.all
This is not possible right now, it must be done in a single step like this:
scoped = Location.within(5, :origin => #somewhere)
results = scoped.all
github.com/geokit/geokit-rails
My approach to solve this, would use the :offset and :limit parameters for the find()
also, there is a distance field for geokit models, :order=>'distance asc'
eg.
page = 0 unless params[:page]
items_per_page = 20
offset = page * items_per_page
#find = Item.find(:all, :origin =>[self.geocode.lat.to_f,self.geocode.lng.to_f], :within=>50, :include=>[:programs], :conditions=>["programs.name = ?", self.name], :order => 'distance asc', :limit => items_per_page, :offset => page)
I have a view with a huge paginated list of records that need filtering.
Users can filter by records a few different ways (such as 'saved' records, 'read' records, and 'mark deleted' records) and I'd like for them to be able to combine these filters any possible way.
My current, flawed, non-functioning approach. The code below does not produce anything unless all of the params are specified and valid:
#view. Set the 'se' filter to true; leave all others as is
<%= link_to list_url(:id=>params[:id], :se=>"true", :st=>params[:st], :re=>params[:re]) do %>
<div class="button">Toggle SE</div>
<% end %>
#controller query. Add whichever params are passed into the conditions for the new page.
#query is paginated and sorted
#records = Record.where("user_id IN (?) AND see = ? AND star = ? AND delete = ? AND like = ?", #users.select("id"), params[:se], params[:st], params[:re]).paginate :page => params[:page], :order => (sort_column + " " + sort_direction)
What is the best way to create this filtering system?
I imagine a client-side sort would be faster than asking the server to become involved every time - is there a simple AJAX way to accomplish this kind of thing? Imagine filters the user can toggle on and off in any combination.
Try this:
conditions = {:user_id => #users.select("id")}
{
:se => :see,
:st => :star,
:del => :delete
}.each{|k1, k2| conditions[k2] = params[k1] unless params[k1].blank?}
#records = Record.where(conditions).paginate(...)
The conditions hash will be filled based on the values present in the params hash.
Edit 1
You can combine conditions hash and array.
#records = Record.where(conditions).where(
":created_at > ?", Date.today - 30).paginate(...)
You can change the user_id condition to what ever you want by specifying
conditions[:user_id] = #user.id
In the above statement, if the RHS is an array, rails automatically generates the IN clause. Otherwise, equality check(=) is performed.
Can also use Anonymous scopes: Combine arrays of conditions in Rails