Disabling ActiveRecord "type" column subclassing


#1

Hi! I have a legacy table that has a column named “type” and need to
remove this automatic subclassing by ActiveRecord. The api pages are
vague about this, and I tried

self.inheritance_column = “xtype”

which seemed to get me half-way. In the validate_on_create method, the
value of self.type was my model Class name.

How would you disable this feature?


#2

Hi! I have a legacy table that has a column named “type” and need to
remove this automatic subclassing by ActiveRecord. The api pages are
vague about this, and I tried

self.inheritance_column = “xtype”

which seemed to get me half-way. In the validate_on_create method, the
value of self.type was my model Class name.

How would you disable this feature?

If you want to check ‘type’ do self[‘type’]…


#3

The short answer is that you can not disable this. The ‘type’ method
is a Ruby method for the class of an object. As stated by Philip you
can access the ‘type’ column data by directly indexing the active
record. You can also create a facade by having methods on the class
that retrieve the ‘type’ column using a different name as in:

def legacy_type
return self[:type]
end

def legacy_type=(value)
self[:type] = value
end

Michael

On Mar 28, 8:34 am, Allen F. removed_email_address@domain.invalid


#4

MichaelLatta wrote in post #227241:

The ‘type’ method is a Ruby method for the class of an object.

This is not a Ruby method. This is part of ActiveRecord, and is used by
Rails to manage single-table inheritance.

I’m adding a solution for future askers. This applies to Rails 3:

class ExampleModel < ActiveRecord::Base
set_inheritance_column do
‘disabled’
end
end

This changes the name of the column that ActiveRecord looks for, to use
for STI. As long as you pick something that doesn’t actually match any
of your column names, it has the effect of disabling inheritance
altogether.


#5

On Feb 18, 2013, at 7:01 PM, Jaime B. wrote:

MichaelLatta wrote in post #227241:

The ‘type’ method is a Ruby method for the class of an object.

This is not a Ruby method. This is part of ActiveRecord, and is used by
Rails to manage single-table inheritance.

While it is true that ‘type’ is not a method in Ruby 1.9, it was in
earlier versions:

irb1.8.7> 1.type
(irb):1: warning: Object#type is deprecated; use Object#class
#1.8.7 => Fixnum

It is something to keep in mind whenever looking at older code.

-Rob


#6

Simply use
class MyModel < ActiveRecord::Base
self.inheritance_column = ‘somthing_not_type’
end