Is there any better way to achieve this in Ruby on Rails?
I'm searching for 11 fields and all are required also, and if not found initialize it.
There will be more required fields adding to it.
This query works perfect for me, but it just doesn't look like the best way to do this.
find_or_initialize_by_make_and_country_and_engine_and_power_and_body_and_doors_and_fuel_and_cylinders_and_transmission_and_gears_and_wheels(model,country,engine,power,body, doors, fuel, cylinders, transmission,gears,wheels)
On rails 3.2 I would do
attributes = {}
Model.where(attributes).first_or_initialize
Documentation http://apidock.com/rails/ActiveRecord/Relation/first_or_initialize
Considering the sheer number of fields you are using, you probably are better off manually finding the record and initializing it if it does not exist:
attributes = {
country: country,
engine: engine,
power: power,
body: body
etc ...
}
record = where(attributes).first
record = new(attributes) unless record
You can define method like this in your model
def self.find_or_initialize_by_field(params)
send("find_or_initialize_by_#{params.keys.join("_and_")}", *params.values)
end
and then you can call this method like
YourModel.find_or_initialize_by_field({country: country, engine: engine})
while using find_or_intialize_by
find by key fields , dont assign all the feilds at once
eg I assume the make is the key field in the model
car = find_or_initialize_by_make(model)
car.update_attributes(country: country,engine: engine,power: power, body: body,doors: doors ,fuel: fuel,cylinders:cylinders,transmission: transmission, gears: gears, wheels: wheels)
http://api.rubyonrails.org/classes/ActiveRecord/Base.html#label-Dynamic+attribute-based+finders
Related
I'd like one of my models, Stones, to be generated at random using pre-defined options I've stored in a set of arrays and hashes. Instead of Create using params from the URL, I'd like new Stones to always be defined using this random generation process. I don't need any user input at all, except that each stone belongs to a given player.
I'm still new to rails; where should I put all this code? I know enough to be able to define the arrays and hashes and randomly select from them when I need to, but I'm not sure where and how to replace the part of the code that draws params from URLs and fills in a new record before it is saved. I know controllers are supposed to be skinny, so do I do this in the model?
Apologies if this is a duplicate. I searched extensively and couldn't find an applicable solution.
Thanks for any help!
I would create a service for this. Something like:
# app/services/stone_creator.rb
class RandomStoneCreator
RANDOM_FOOS = ['bar', 'baz', 'bat']
def self.call(user)
Stone.create!({
foo: RANDOM_FOOS.sample,
user: user
})
end
end
And then anywhere that you need a new random stone you can call it like:
random_stone = RandomStoneCreator.call(current_user)
Let's say I have a User with attributes name and badge_number
For a JavaScript autocomplete field I want the user to be able to start typing the user's name and get a select list.
I'm using Materialize which offers the JS needed, I just need to provide it the data in this format:
data: { "Sarah Person": 13241, "Billiam Gregory": 54665, "Stephan Stevenston": 98332 }
This won't do:
User.select(:name, :badge_number) => { name: "Sarah Person", badge_number: 13241, ... }
And this feels repetitive, icky and redundant (and repetitive):
user_list = User.select(:name, :badge_number)
hsh = {}
user_list.each do |user|
hsh[user.name] = user.badge_number
end
hsh
...though it does give me my intended result, performance will suck over time.
Any better ways than this weird, slimy loop?
This will give the desired output
User.pluck(:name, :badge_number).to_h
Edit
Though above code is one liner, it still have loop internally. Offloading such loops to database may improve the performance when dealing with too many rows. But there is no database agnostic way to achieve this in active record. Follow this answer for achieving this in Postgres
If your RDBMS is Postgresql, you can use Postgresql function json_build_object for this specific case.
User.select("json_build_object(name, badge_number) as json_col")
.map(&:json_col)
The whole json can be build using Postgresql supplied functions too.
User.select("array_to_json(array_agg(json_build_object(name, badge_number))) as json_col")
.limit(1)[0]
.json_col
Is there a short-hand way of querying a Rails database for any record that has a field containing a specific piece of text? I know I could code every field with a .where("field_name LIKE ?", "my text"), but I have several fields and am wondering if there is a shorter way of doing this.
Thanks in advance.
I do not know of a framework-way to do so. You could code something using
my_attributes = YourModel.attributes
# delete attributes you do not need, like `id` etc.
# or just create an array with your desired attributes,
# whichever way is faster
queries = my_attributes.map { |attr| "#{attr} LIKE %insert_your_text_here%" }
# Do not use this if the text your looking for is provided by user input.
built_query = queries.join(" OR ")
YourModel.where(built_query)
This could bring you closer to your goal. Let me know if this makes sense to you.
edit: The answer https://stackoverflow.com/a/49458059/299781 mentions Ransack. That's a nice gem and takes the load off of you. Makes it easier, nicer and performs better :D
Glad you like this, but pay attention that you make your app open for sql injection, if you take user-input as the text you are looking for. (with this solution) Ransack would alleviate that.
class MyModel
scope :search_like, -> (field_name, search_string) {where("#{field_name} LIKE ?", "%#{search_string}%")}
end
then you can call it like:
MyModal.search_like('name', 'foobar')
UPDATE based on #holgar answer but beware if not indexed these searches can be slow on large data sets:
class MyModel
def self.multi_like(search_string)
my_attributes = [:first_name, :last_name] # probalby only use string fields here
queries = my_attributes.map { |attr| "#{attr} LIKE '%#{search_string}%'" }
where(queries.join(" OR "))
end
end
If you want full fledge text search based on params then you can use ransack gem
I'm not sure if this is just a lacking of the Rails language, or if I am searching all the wrong things here on Stack Overflow, but I cannot find out how to add an attribute to each record in an array.
Here is an example of what I'm trying to do:
#news_stories.each do |individual_news_story|
#user_for_record = User.where(:id => individual_news_story[:user_id]).pluck('name', 'profile_image_url');
individual_news_story.attributes(:author_name) = #user_for_record[0][0]
individual_news_story.attributes(:author_avatar) = #user_for_record[0][1]
end
Any ideas?
If the NewsStory model (or whatever its name is) has a belongs_to relationship to User, then you don't have to do any of this. You can access the attributes of the associated User directly:
#news_stories.each do |news_story|
news_story.user.name # gives you the name of the associated user
news_story.user.profile_image_url # same for the avatar
end
To avoid an N+1 query, you can preload the associated user record for every news story at once by using includes in the NewsStory query:
NewsStory.includes(:user)... # rest of the query
If you do this, you won't need the #user_for_record query — Rails will do the heavy lifting for you, and you could even see a performance improvement, thanks to not issuing a separate pluck query for every single news story in the collection.
If you need to have those extra attributes there regardless:
You can select them as extra attributes in your NewsStory query:
NewsStory.
includes(:user).
joins(:user).
select([
NewsStory.arel_table[Arel.star],
User.arel_table[:name].as("author_name"),
User.arel_table[:profile_image_url].as("author_avatar"),
]).
where(...) # rest of the query
It looks like you're trying to cache the name and avatar of the user on the NewsStory model, in which case, what you want is this:
#news_stories.each do |individual_news_story|
user_for_record = User.find(individual_news_story.user_id)
individual_news_story.author_name = user_for_record.name
individual_news_story.author_avatar = user_for_record.profile_image_url
end
A couple of notes.
I've used find instead of where. find returns a single record identified by it's primary key (id); where returns an array of records. There are definitely more efficient ways to do this -- eager-loading, for one -- but since you're just starting out, I think it's more important to learn the basics before you dig into the advanced stuff to make things more performant.
I've gotten rid of the pluck call, because here again, you're just learning and pluck is a performance optimization useful when you're working with large amounts of data, and if that's what you're doing then activerecord has a batch api you should look into.
I've changed #user_for_record to user_for_record. The # denote instance variables in ruby. Instance variables are shared and accessible from any instance method in an instance of a class. In this case, all you need is a local variable.
Im creating a simple rails app to modify data in an existing mongo database. I'm using mongoid for the interaction and can read/destroy objects just fine.
The problem comes is my mongo document has a 'node' which is a bunch of key value pairs with vary depending on the record. When i load the record like so:
MongoObject.find(BSON::ObjectId('ABC1234567890'))
=> #<MongoObject _id: ABC1234567890, node: {"totallogins"=>11, "id"=>"logIns"}>
I'm using a standard rails form to update the values so the post data looks like:
{"commit"=>"Edit", "utf8"=>"✓", "id"=>"ABC1234567890", "mongo_object"=>{"node"=>{"totallogins"=>"12", "id"=>"logIns"}}
If i then do:
#mongo_object.update_attributes(params[:mongo_object])
This works but changes the datatype of "totallogins" from an int to a string because the post data is a string.
Now active record deals with this itself but i need a solution that will work with mongoid.
Any ideas how i can do this?
Thanks. Unfortunately i can't as the fields for node are totally dynamic so i can't define them. I've come up with the following solution but its a tad ugly:
#mongo_object.node.each do |k,v|
new_value = params[:mongo_object][:node][k.to_sym]
new_value = new_value.to_i if v.class == Fixnum
#mongo_object.node[k] = new_value
end
#mongo_object.save
If you make the node an embedded_document, then you can explicitly set the field types when you declare them.
class Node
include Mongoid::Document
embedded_in :mongo_object
field :totallogins, type: Integer
...
end
http://mongoid.org/docs/documents/ mentions how to deal with types; perhaps make sure your type is an Integer?