https://github.com/ggonnella/attr_hidden

Rails / ActiveRecord - Hide attributes in a model (particularly useful for Single Table Inheritance)
https://github.com/ggonnella/attr_hidden

Last synced: 3 months ago
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Rails / ActiveRecord - Hide attributes in a model (particularly useful for Single Table Inheritance)

• Host: GitHub
• URL: https://github.com/ggonnella/attr_hidden
• Owner: ggonnella
• License: mit
• Created: 2008-08-22T18:48:25.000Z (almost 17 years ago)
• Default Branch: master
• Last Pushed: 2008-09-06T15:06:39.000Z (over 16 years ago)
• Last Synced: 2025-01-16T16:23:22.549Z (4 months ago)
• Language: Ruby
• Homepage:
• Size: 82 KB
• Stars: 4
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README
  • License: MIT-LICENSE

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README

        
This is a Rails plugin, which was created for Rails 2.1

but might work also for other Rails versions.

It does not contain unit tests, so if you would like to 

collaborate, this would be a nice addition.

Although this plugin does not require STI, it is probably

only really useful with single table inheritance.

Example usage with STI

======================

Let's use the example of STI given by Martin Fowler at:

http://www.martinfowler.com/eaaCatalog/singleTableInheritance.html

table players:

name, club, batting_average, bowling_average, type

type may be: Footballer, Cricketer, Bowler

The attribute bowling_average will always be NULL in any record with type 

Cricketer or Footballer. The same is true for club in Cricketer or Bowler. 

so using ActiveRecord you have: 

class Player < ActiveRecord::Base

end

class Footballer < Player

end

class Cricketer < Player

end

class Bowler < Cricketer

end

however when you use an object of the class Bowler you can still access "club",

which make sense only for Footballer; this plugin comes in hand in this situation.

The point of this plugin is to hide from the object instance in the 

object-relational mapping the columns which are anyway always NULL in some 

of these classes.

using attr_hidden: 

class Player < ActiveRecord::Base

end

class Footballer < Player

  attr_hidden :batting_average, :bowling_average

end

class Cricketer < Player

  attr_hidden :club, :bowling_average

end

class Bowler < Cricketer

  attr_not_hidden :bowling_average

end

now each class sees only the columns which are meaningful for them.