has many through and STI

rubyonrails-talk
1

Im using ruby 1.9.2 and Rails 3.0.3.

I have the following models

class Property < ActiveRecord::Base

class Feature < ActiveRecord::Base

class DefaultFeature < Feature

class CustomFeature < Feature

class PropertyFeature < ActiveRecord::Base

One Property can have many Features, and one Feature is associated with many Properties (joined through PropertyFeature model). There are two kinds of Features: DefaultFeatures and CustomFeatures, for what Im using single table inheritance. Both kinds of Features have exactly the same fields, but i need to differentiate them in my application.

What i want to achieve, if possible, is being able to access Features from a Property instance like this:

a_property.features

a_property.custom_features

a_property.default_features

And also add features to a property:

a_property.custom_features << CustomFeature.new

a_property.features << CustomFeature.new

The closest solution i could think of is this one:

http://pastie.org/1499280

The problem I’m having is that when i call a_property.custom_features it brings all features from the property: custom AND default ones.

I’ve already tried making polymorphic the belongs_to :feature association in the PropertyFeature model, but it raised an ActiveRecord::HasManyThroughAssociationPolymorphicError exception, so i assume rails is not supposed to work like that.

I’d appreciate any help on how to do this (i’ve tried everything i could think of). Maybe my approach is wrong to begin with, in which case i’d love to hear a better way to to this.

thanks!

2

Not fully understanding your problem, have you tried named_scope?

3

Hello!

Im using ruby 1.9.2 and Rails 3.0.3.

I have the following models

class Property < ActiveRecord::Base class Feature < ActiveRecord::Base class DefaultFeature < Feature class CustomFeature < Feature class PropertyFeature < ActiveRecord::Base

One Property can have many Features, and one Feature is associated with many Properties (joined through PropertyFeature model). There are two kinds of Features: DefaultFeatures and CustomFeatures, for what Im using single table inheritance. Both kinds of Features have exactly the same fields, but i need to differentiate them in my application. What i want to achieve, if possible, is being able to access Features from a Property instance like this: a_property.features a_property.custom_features a_property.default_features

And also add features to a property: a_property.custom_features << CustomFeature.new a_property.features << CustomFeature.new

The closest solution i could think of is this one:http://pastie.org/1499280

The problem I'm having is that when i call a_property.custom_features it brings all features from the property: custom AND default ones. I've already tried making polymorphic the belongs_to :feature association in the PropertyFeature model, but it raised an ActiveRecord::HasManyThroughAssociationPolymorphicError exception, so i assume rails is not supposed to work like that.

I'd appreciate any help on how to do this (i've tried everything i could think of). Maybe my approach is wrong to begin with, in which case i'd love to hear a better way to to this.

The issue is that the :source association you're using doesn't distinguish between the types. The quickest way might be to add with a specific type.

--Matt Jones