CODEWITHSUNDEEP
ruby-on-railsruby
max pleaner
max pleaner

Reputation: 26768

Why is attr_accessor necessary in Rails?

I occasionally see attribute accessors/readers/writers in the code for models. Are these necessary if I want to be able to update attributes from the view / controller code?

I am a beginner so I am really talking about basic applications.

Upvotes: 27

Views: 19681

Answers (4)

jorgedjr21
jorgedjr21

Reputation: 111

Generally, i use attr_accessor for attributes that is not in model/database, but i think it's not necessary using them.

Upvotes: 0

Nikolay
Nikolay

Reputation: 1392

Generally it is a pretty good idea to decorate attr_accessor for anything on a model that is not an actual column in the SQL table. Rails 4 or not. This gives you clear understanding of what's in the model and what is persisted.

Upvotes: 3

colinm
colinm

Reputation: 4288

attr_accessor is a core feature of Ruby and is used to generate instance variables with getter and setter methods. Its use is never required in basic Ruby (it's a convenience).

In the case of ActiveRecord models, getters and setters are already generated by ActiveRecord for your data columns. attr_accessor is not needed or desirable.

If you have additional instance data you don't need to persist (i.e. it's not a database column), you could then use attr_accessor to save yourself a few lines of code.

The similarly-named attr_accessible — which is frequently seen in Rails code and confused with attr_accessor — is a deprecated method of controlling mass assignment within ActiveRecord models. Rails 4 doesn't support it out of the box; it has been replaced by Strong Parameters, which allows more granular control.

Upvotes: 60

Kaleidoscope
Kaleidoscope

Reputation: 3627

If you declare an attr_accessor then you can use it as a virtual attribute, which is basically an attribute on the model that isn't persisted to the database.

Example case: you declare attr_accessor :password in your User model so that you can use it as a field in a new user form. When you receive their password in the corresponding create action, you can derive a hashed_password, persist it to the database, and discard the given password (which is done automatically at the end of the request).

Upvotes: 27

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