Are there any 'protected' names you should avoid in Rails models?

Question

I'm new to Rails and I just wondered if there were any protected names you should avoid using in your models? For example, would the following be valid:

class CreateModel < ActiveRecord::Migration
  def change
    create_table :model do |t|
      t.string :hash
      t.integer :count

      t.timestamps
    end
  end
end

I realise has probably isn't a great name for a property, but it's a pure example.

Edit: All the responses were good, but I've chosen my accepted answer because it contains a link to a huge list of protected attributes.

You're right it is a duplicate! I didn't find that one searching though. — squarefrog, Mar 09 '14 at 20:25

score 3 · Answer 1 · answered Mar 09 '14 at 20:09

Avoid class names, if they are defined:

!!defined? Class  # => true
!!defined? Model  # => false

Avoid column names within this list:

id - Reserved for primary keys
lock_version
type - single table inheritance and must contain a class name
table_name_count - Reserved for counter cache
position - Reserved for acts_as_list
parent_id - Reserved for acts_as_tree
lft - Reserved for acts_as_nested_set
rgt - Reserved for acts_as_nested_set
quote - Method in ActiveRecord::Base which is used to quote SQL
template

I don't think those will be a problem. Thanks for the `defined` headsup! — squarefrog, Mar 09 '14 at 20:28

score 1 · Answer 2 · answered Mar 09 '14 at 19:49

1

I can remember only two:

type, because Rails treats this property as a type of parent object in polymorphic objects.
order and any other SQL commands/statements/etc., because Rails generating SQL queries is using them and usually an exception occurs.

answered Mar 09 '14 at 19:49

Maksim Gladkov

3,051
1
14
16

I see. They both make sense and should be easy to remember. – squarefrog Mar 09 '14 at 20:26

score 1 · Accepted Answer · edited May 23 '17 at 12:21

1

I personally ran into an issue where I named my model record:

Other than that:

edited May 23 '17 at 12:21

Community

1
1

answered Mar 09 '14 at 19:52

wpp

7,093
4
33
65

Superb - thanks for the links! – squarefrog Mar 09 '14 at 20:26

score 1 · Answer 4 · answered Mar 10 '14 at 08:47

I had an issues with an external db and a column named "hash". The offending column can be ignored in this manner:

class SomeClass < ActiveRecord::Base
  class << self # Class methods
    alias :all_columns :columns 

    def columns 
      all_columns.reject {|c| c.name == 'hash'} 
    end 
  end 
end

Are there any 'protected' names you should avoid in Rails models?

4 Answers4

Linked