CODEWITHSUNDEEP
ruby-on-railsactiverecord
jVenki
jVenki

Reputation: 93

Restrict the columns represented in ActiveRecord

How to change ActiveRecord so that it always has a restricted set of columns. I dont want all the columns in the backened table to present in the Model. This unnecessarily bloats the ActiveRecord's memory footprint as well as the time taken to query the record.

There are attributes like select (ar.rubyonrails.org/classes/ActiveRecord/Base) which can be used to SELECT only few columns. But is there any way we can force ActiveRecord to never query those columns inspite of the user performing just find without specifying :select all the time.

Upvotes: 7

Views: 1002

Answers (2)

Syed Aslam
Syed Aslam

Reputation: 8807

Can't you do with a scope: 

IGNORED = %w( id created_at updated_at )
scope :filtered, lambda { select( cols ) }

def self.cols
  attribute_names = []
  attributes = self.columns.reject { |c| IGNORED.include?( c.name ) }

  attributes.each { |attr| attribute_names << attr.name }
  attribute_names
end

Model.filtered
[#<Model name: "Test 2", reg_num: "KA 02", description: "aldsfjadflkj">]

Upvotes: 2

Chris Bailey
Chris Bailey

Reputation: 4136

use default_scope

e.g.

class MyModel < ActiveRecord::Base
  default_scope select("column1, column2, column3")

  ...
end

Upvotes: 10

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