Custom SQL query without Corresponding Table

Question

I have a SQL query that isn\'t table-specific and I don\'t know how to handle it with Ruby On Rails.

Here my SQL query (you don\'t need to understand it):

SELE         


        

Answer 1

You can also grab the ActiveRecord connection and call select_all:

ActiveRecord::Base.connection.select_all('select * from foo').each do |e|
  puts e.inspect
end

Answer 2

You can grab a db connection directly from ActiveRecord::Base, but it's not as useful as extending AR::Base, because helpful methods like sanitize_sql are protected.

class ComplexQueries < ActiveRecord::Base
  def self.my_query
    # Notice how you can, and should, still sanitize params here. 
    self.connection.execute(sanitize_sql(["select * from foo limit ?", 10]))
  end
end

results = ComplexQueries.my_query
results.each_hash{|h| puts h.inspect}

Answer 3

If you want to create classes (models) that are not backing to a database you need to not state that they are inheriting from ActiveRecord.

Do

class RecentActivity

Instead of

class RecentActivity < ActiveRecord::Base

That being said, it still might be helpful to get some more information on what you are trying to do: for example if you want to have something like "comments" or "pictures" on multiple different things like an article, or someones profile or blogpost all within the same application, I'd recommend checking out PolyMorphic Associations.