How do you combine/merge two resultsets using mongoid? - ruby-on-rails

How do I get a single resultset for a Student that also includes the classroom information - description and the name of the student? Is this possible?
Classroom has a 1-to-N relationship with Student in my current example
Classrooms.first currently returns
Classroom {
:_id => "5222da075d39f3e4e802000a",
:description => "Learn english",
:student_id => "50f9d5bc5d39f30ebb010004"
}
Classroom.first.student.first currently only returns:
Student {
:_id => "50f9d5bc5d39f30ebb010004",
:name => "Michael",
:classroom_id => "5222da075d39f3e4e802000a"
}

here is one solution:-
Classroom.first.attributes.merge(Classroom.first.student.first.attributes)
It will return a hash with both the model values

Related

Can't access data in ActiveHash

I'm using the Gem active_hash https://github.com/zilkey/active_hash to create models for simple data that I don't want to create DB tables for.
For example, I have this model setup for FieldTypes:
class FieldType < ActiveHash::Base
self.data = [
{:id => 1, :name => "text", :friendly_name => "Text"},
{:id => 2, :name => "textarea", :friendly_ => "Text Area"},
{:id => 3, :name => "image", :friendly_ => "Image"},
]
end
And I'm trying to list these field types for a select:
def field_types_for_select
#FieldType.all.order('name asc').collect { |t| [t.friendly_name, t.name] }
FieldType.pluck(:friendly_name, :name)
end
But I get an error that order, collect or pluck are not defined.
How do I access this data? This works fine on other models, just not ActiveHash ones. According to the docs the model should work the same as ActiveRecord but I don't seem to be able to access it the same. FieldType.all works, but other methods do not.
Pluck isn't defined on ActiveHash::Base. It is defined on ActiveRecord::Relation::Calculations, and it's purpose is to produce a SQL select for the columns you specify. You will not be able to get it to work with ActiveHash.
You can, however, define your own pluck on your FieldType model.
def self.pluck(*columns)
data.map { |row| row.values_at(*columns) }
end
Or query the data directly:
FiledType.data.map { |row| row.values_at(:friendly_name, :name) }

ruby on rails: ElasticSearch / Tire dynamic search on multiple indices

I've done a bunch of searching and I haven't been able to get an answer to this question - hopefully this isn't a repeat (apologies if it is)...
Preface: I'm using Rails & Tire to perform ElasticSearch.
I have an object, Place, with attributes "name", "city", "state", and "zip". They are indexed as follows:
indexes :name, :type => 'multi_field', :fields => {
:name => { :type => 'string', :analyzer => 'snowball' },
:"name.exact" => { :type => 'string', :index => :not_analyzed }
}
indexes :city
indexes :state
indexes :zip
There are three conditions for searching: 1. Name only, 2. (City, State OR Zip), 3. Name AND (City, State OR Zip).
My code for the "query" block is:
if (City, State).present?
boolean do
must { string "name:#{name}*" } if name.present?
must { string "city:#{city_state}*" }
must { string "state:#{city_state}*" }
end
elsif (Zip).present?
boolean do
must { string "name:#{name}*" } if name.present?
must { string "zip:#{query_parameters["zip"]}*" }
end
else
string "name:#{name}*" }
end
The aforementioned search conditions #1 and #2 work as expected against multiple tests. However, condition 3 does not - it seems to only pay attention to the "name" field. I'm assuming it has something to do with using the "city_state" variable to search on both "city" and "state"... But I'm doing this because a user can enter either "Chicago" or "Illinois" in the City, State / Zip text box and the search should still work, using either the geographic center of Chicago or the geographic center of Illinois, respectively.
Anything obvious I'm doing wrong?
However, condition 3 does not - it seems to only pay attention to the "name" field
Errr, isn't
string "name:#{name}*"
telling it to do exactly that?
or did you mean to just do
string "#{name}"

Constructing a new object in Rails that is part of an active record association

This is just a simple question. I was trying to create a new object in Rails by passing in parameters to the constructor. However, when I execute the code, I get
SQLite3::SQLException: no such column: awards.user_id: SELECT "awards".* FROM "awards" WHERE "awards"."user_id" = 1
which means the object isn't being constructed properly. Should I be using create instead of new? That isn't working either.
def refresh_awards(user)
new_awards = []
if (user.karma < 40 ) #test award
a = Award.new(:name => "Nobody Award", :description => "From Jonathan", :category => "Community", :value => 1337, :level => 0, :handle => "nobody_award")
user.awards.append(a)
new_awards.append(a)
end
new_awards.each do |a|
flash[:notice] = "You received the " + a.name + "!"
end
end
Have you add has_many :awards to the User model? Have you added belongs_to :user to the Award model? Have you added the column user_id to the Award model (using a migration)? You'll need to do these three things to be able to use the user.awards method you're using. Read the Rails Guide on Associations for more detail.
Also, append isn't a Ruby method - the closest method would be <<. You would use it like this:
a = Award.new(:name => "Nobody Award", :description => "From Jonathan", :category => "Community", :value => 1337, :level => 0, :handle => "nobody_award")
user.awards << a
But you could neaten this into one line of code using the create method:
a = user.awards.create(:name => "Nobody Award", :description => "From Jonathan", :category => "Community", :value => 1337, :level => 0, :handle => "nobody_award")
EDIT: To create the user_id column in the Award model, run the following code from terminal (while in your app's directory):
rails generate migration AddUserIdToAward user_id:integer
rake db:migrate

How do I seed a belongs_to association?

I would like to seed my Products and assign them to a specific User and Store.
Product.rb
class Product < ActiveRecord::Base
belongs_to :user
belongs_to :store
def product_store=(id)
self.store_id = id
end
end
Note: Store belongs_to Business (:business_name)
Seed.rb
This is my basic setup:
user = User.create(:username => 'user', :email => 'user2#email.com')
store = Store.create(:business_name => 'store', :address => 'Japan')
I attempted these but they did not work:
# This gives random ID's ranging from 1 to 4425!?
user.products.create([{:name => "Apple", :product_store => Store.find_by_address('San Francisco, USA')}])
# This gives me undefined method 'walmart'.
user.store.products.create([ {:name => "Apple"} ])
Is there a way to set the ID's so I can associate my Products to a Store and User?
UPDATE -
I have tried the answers below and still came out unsuccessful. Does anyone know of another way to do this?
Although it sounds like you found a workaround, the solution may be of interested to others.
From your original seeds.rb
user = User.create(:username => 'user', :email => 'user2#email.com')
store = Store.create(:business_name => 'store', :address => 'Japan')
Create the store
Store.create({
user_id: user.id
store_id: store.id
}, without_protection: true)
In the original code snipped "user" and "store" variables are declared. The code assigns user_id / store_id (the model columns inferred by the belongs_to relationship in the Store model) to the id values that are present in the "user" and "store" variables.
"without_protection: true" turns off bulk assignment protection on the id fields. This is perfectly acceptable in a seeds file but should be used with extreme caution when dealing with user provided data.
Or alternatively create your stores.
Then extract the correct one
e.g.
store = Store.find_by_business_name('Test Store')
and then create it based on that
e.g.
store.products.create(:product_name => "Product Test", :price => '985.93')
This will then set the relationship id for you,
If I'm not mistaken, you're just trying to do this.
user = User.create(:username => 'usertwo', :email => 'user2#email.com')
walmart = Store.create(:business_name => 'Walmart', :address => 'San Francisco, USA')
user.products.create(:name => 'Apple', :store => walmart)
Anything else required here that I'm not seeing?
Try doing this
store_1 = Store.new(:business_name => 'Test Store',
:address => 'Test Address',
:phone_number => '555-555-555')
store_1.id = 1
store_1.save!
The trick is not to set the id within the hash as it is protected.
Scott
What I did was update the particular products to a certain user, see this question:
Can I update all of my products to a specific user when seeding?
You could just create a series of insert satements for this "seed migration", including the record Id for each user, store, product etc. You might have to update database sequences after this approach.
Another approach
Create the initial records in you Rails app, through the GUI / web.
Then use something like Yaml-db. So you can dump the data to a yaml file. You can now edit that file (if necessary) and use that same file to seed another instance of the db with "rake db:load"
Either way.... You know the Ids will not be shifting around on you when these objects are created in the new db instance.
I'm sure there are other ways to do this... Probably better ones, even.
Here is a link to a write-up I did a while back for using yaml_db to seed an oracle database
http://davidbharrison.com/database_seeding_oracle
Try this:
User.destroy_all
Product.destroy_all
user = User.create!([{:username => 'usertwo', :email =>'user2#email.com'},
{:username => 'userthree', :email => user3#email.com}])
user.each_with_index do |obj, index|
Product.create!([{ :product_name => 'product #{index}', :user_id => obj.id }])
end
The table would look like this:
Here's how I prefer to seed an association in rails 6
#teacher = Teacher.new(name: "John")
#student = #teacher.build_student(name: "Chris")
#teacher.save!
#student.save!

Mongoid: select embedded objects that fits number of options

I have got this structure
class House
include Mongoid::Document
embeds_many :inhabitants
end
class Inhabitant
include Mongoid::Document
embedded_in :house
field :name
field :gender
field :age
end
I can get all houses where females live:
houses = House.where("inhabitants.gender" => "female")
But how can I get all houses where females under age 50 live? How can I specify more than one condition for embedded object?
To apply multiple conditions to each entry in an array, you should use the $elemMatch operator. I'm not familiar with Mongoid, but here's the MongoDB shell syntax for your query modified to use $elemMatch:
> db.house.find({inhabitants: {$elemMatch: {gender: "female", age: {$lt: 50}}}})
Try this:
houses = House.where("inhabitants.gender" => "female", "inhabitants.age" => {"$lt" => 50})
Combining conditions:
MongoDB query:
db.houses.find({'inhabitants.age' : {$in: {$lt: 50}}})
Mongoid:
houses = House.where('inhabitants.age' => {'$in' => {'$lt' => 50}})

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