Geek asks and answers

What is the Rails ActiveRecord (x) lookup method that is equivalent to lazy-rated-scope? How to reorganize ActiveRecord search?

Is the Rails' find (x) method on the model lazy? If not, what is equivalent?

I am new to Rails, so I discovered that I am writing such areas:

class Course < ActiveRecord::Base
  scope :by_instructor_id, lambda { |instructor_id| where(:instructor_id => instructor_id) }
  scope :by_course_template_id, lambda { |course_template_id| where(:course_template_id => course_template_id ) }
  scope :by_company_id, lambda { |company_id| joins(:instructor).merge(CompanyUser.by_company_id(company_id)) }
end

This is not a lot of work, but now I ask myself ... if Rails provided them with scope, I would not have to write them.

So, does Rails offer? Can I do something like the code below and make it just one database call?

Company.find(params[:id]).instructors.courses

instead

Course.by_company_id(params[:id])

What is right? I know that Course.by_company_id(params[:id])this is only 1 database call. This is very well known for writing SQL or queries in Hibernate. But if you can write it in another way, maybe you need to?

Company.find(params[:id]).instructors.courses, . , , 3 , , , Company.find(x) . ?

+3
2

#scoped #find:

user = User.scoped.instructors.courses.find(params[:id])
0

find id , , .

# company
def company  
  @company ||= Company.find(params[:id])  
end  
helper :company

#view
<%= company.name %>

, RailsCast -

0

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