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Eager load polymorphic association in Rails (clear code example included)

Rails :include vs. :joinsEager loading of polymorphic associations in ActiveRecordrails 3, joining on more three tablesRails: Structuring a query involving a polymorphic association and STIIn Rails, how can I make ActiveRecord associations for two models that reference each other in different ways?Eager load polymorphicrails 4 scope through multiple has_one associationsEager load (includes) polymorphic associationRails Multiple checkboxes with associated Text fieldsRails - get polymorphic children from collection as ActiveRecord::Relation

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0

I have following db (Postgresql) structure in Rails 5:

class Book < ApplicationRecord
 belongs_to :location
end

class Song < ApplicationRecord
 belongs_to :location
end

class Location < ApplicationRecord
 # position INT
end

class Item < ApplicationRecord
 belongs_to :product, polymorphic: true # Book or Song
 has_one :location, through: :product
end

# Expected result
Item.includes(product: :location).order('locations.position ASC')
Item.first.location

# Actual result
# ActiveRecord::EagerLoadPolymorphicError (Cannot eagerly load the polymorphic association :product)

But I have trouble for referencing Location through polymorphic Product. May be I missed some options here and selected wrong DB structure? Could you advise some "Rails way" workarounds here, rather then raw sql?

ruby-on-rails ruby postgresql activerecord

share|improve this question

asked Mar 24 at 9:52

MolfarMolfar

5291033

add a comment | 

0

I have following db (Postgresql) structure in Rails 5:

class Book < ApplicationRecord
 belongs_to :location
end

class Song < ApplicationRecord
 belongs_to :location
end

class Location < ApplicationRecord
 # position INT
end

class Item < ApplicationRecord
 belongs_to :product, polymorphic: true # Book or Song
 has_one :location, through: :product
end

# Expected result
Item.includes(product: :location).order('locations.position ASC')
Item.first.location

# Actual result
# ActiveRecord::EagerLoadPolymorphicError (Cannot eagerly load the polymorphic association :product)

But I have trouble for referencing Location through polymorphic Product. May be I missed some options here and selected wrong DB structure? Could you advise some "Rails way" workarounds here, rather then raw sql?

ruby-on-rails ruby postgresql activerecord

share|improve this question

asked Mar 24 at 9:52

MolfarMolfar

5291033

add a comment | 

I have following db (Postgresql) structure in Rails 5:

class Book < ApplicationRecord
 belongs_to :location
end

class Song < ApplicationRecord
 belongs_to :location
end

class Location < ApplicationRecord
 # position INT
end

class Item < ApplicationRecord
 belongs_to :product, polymorphic: true # Book or Song
 has_one :location, through: :product
end

# Expected result
Item.includes(product: :location).order('locations.position ASC')
Item.first.location

# Actual result
# ActiveRecord::EagerLoadPolymorphicError (Cannot eagerly load the polymorphic association :product)

But I have trouble for referencing Location through polymorphic Product. May be I missed some options here and selected wrong DB structure? Could you advise some "Rails way" workarounds here, rather then raw sql?

ruby-on-rails ruby postgresql activerecord

share|improve this question

asked Mar 24 at 9:52

MolfarMolfar

5291033

class Book < ApplicationRecord
 belongs_to :location
end

class Song < ApplicationRecord
 belongs_to :location
end

class Location < ApplicationRecord
 # position INT
end

class Item < ApplicationRecord
 belongs_to :product, polymorphic: true # Book or Song
 has_one :location, through: :product
end

# Expected result
Item.includes(product: :location).order('locations.position ASC')
Item.first.location

# Actual result
# ActiveRecord::EagerLoadPolymorphicError (Cannot eagerly load the polymorphic association :product)

share|improve this question

asked Mar 24 at 9:52

MolfarMolfar

5291033

share|improve this question

asked Mar 24 at 9:52

MolfarMolfar

5291033

asked Mar 24 at 9:52

MolfarMolfar

5291033

asked Mar 24 at 9:52

MolfarMolfar

5291033

2 Answers
2

active

oldest

votes

1

I don't understand your items model but polymorphic is normally set up like this:

class Book < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Song < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Location < ApplicationRecord
 belongs_to :locateable, polymorphic: true
end

But please refer to documentation on polymorphic relation

share|improve this answer

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

add a comment | 

1

The reason is you doing it wrong.in your code you are saying that product is going to be polymorphic but still with wrong syntax and not including that polymorphic association in other models ..check out the above answer and do check the rails official guide for further clarification.

share|improve this answer

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

add a comment | 

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1

I don't understand your items model but polymorphic is normally set up like this:

class Book < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Song < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Location < ApplicationRecord
 belongs_to :locateable, polymorphic: true
end

But please refer to documentation on polymorphic relation

share|improve this answer

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

add a comment | 

1

I don't understand your items model but polymorphic is normally set up like this:

class Book < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Song < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Location < ApplicationRecord
 belongs_to :locateable, polymorphic: true
end

But please refer to documentation on polymorphic relation

share|improve this answer

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

add a comment | 

I don't understand your items model but polymorphic is normally set up like this:

class Book < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Song < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Location < ApplicationRecord
 belongs_to :locateable, polymorphic: true
end

But please refer to documentation on polymorphic relation

share|improve this answer

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

class Book < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Song < ApplicationRecord
 has_one :location, as: :locateable, class_name: Location
end

class Location < ApplicationRecord
 belongs_to :locateable, polymorphic: true
end

share|improve this answer

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

answered Mar 24 at 12:06

lacostenycoderlacostenycoder

5,07621431

1

The reason is you doing it wrong.in your code you are saying that product is going to be polymorphic but still with wrong syntax and not including that polymorphic association in other models ..check out the above answer and do check the rails official guide for further clarification.

share|improve this answer

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

add a comment | 

1

The reason is you doing it wrong.in your code you are saying that product is going to be polymorphic but still with wrong syntax and not including that polymorphic association in other models ..check out the above answer and do check the rails official guide for further clarification.

share|improve this answer

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

add a comment | 

The reason is you doing it wrong.in your code you are saying that product is going to be polymorphic but still with wrong syntax and not including that polymorphic association in other models ..check out the above answer and do check the rails official guide for further clarification.

share|improve this answer

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

share|improve this answer

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124

answered Mar 25 at 1:19

The Digital AcademyThe Digital Academy

124