Models can associate in three main ways: one to many, one to one, and many to many.
This is tagged primarily in Ruby community. Models can associate in three main ways: one to many, one to one, and many to many.
Questions tagged [model-associations]
865 questions
5
votes
3 answers
CakePHP 3.0 Can't save hasMany associated data
I've problem when saving data with hasMany association
This is my table
1) post table: each item has an unique id.
id | title | ...
1 | Aloha | ...
2) images table
id | post_id | image | ...
1 | 1 | abc.jpg | ...
2 | 1 | efg.jpg…
rslhdyt
- 149
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5
votes
2 answers
Rails 3 can't perform validation for persited object when use collection_singular_ids=ids method
Is there any way to avoid automatically saving object while assigning collection attributes(collection_singular_ids=ids method)?
for example, I have the following Test and Package model, Package has many tests. User can build package bundle with…
Manivannan Jeganathan
- 513
- 1
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5
votes
1 answer
Data Modeling 3 Way Table has_many association
I am attempting to build a table to handle both the location and category a certain campaign has been set to with the following model associations:
class Campaign < ActiveRecord::Base
has_many :campaign_category_metro_bids, dependent: :destroy
…
Sauron
- 6,399
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5
votes
1 answer
Undefined method for nil class in Rspec test
So, I have a Game class that can have many Versions, and each Version can have many GameStats. I have my Each Version belongs_to a Game, and each GameStat belongs_to a Version and has_one Game through the Versions. In my tests, when I test for…
Benedict Lee
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5
votes
2 answers
Source Reflection Errors with has_many :through
I'm attempting to create a system where my site's users can favorites pages. Those pages have two types, either clubs or sports. So, I have four models, associated as such:
User Model:
class User < ActiveRecord::Base
..
has_many…
Alex LaFroscia
- 961
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5
votes
1 answer
Plural Name in Association in Rails
I have user model and a car model
I want to have a model which will hold the settings for each car and each user
so I do
class CarSettings < ActiveRecord::Base
belongs_to :user
belongs_to :car
end
for user:
has_many :car_settings
and for…
Nick Ginanto
- 31,090
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4
votes
1 answer
Efficient Join queries - Can it be done using ActiveRecord
I have 4 models, A, B, C and D
class A < ActiveRecord::Base
has_many :B
has_many :C, :through => :B
end
class B < ActiveRecord::Base
belongs_to :A
has_many :C
has_many :D, :through => :C
end
class C < ActiveRecord::Base
…
Atarang
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4
votes
2 answers
How can I check if one ActiveRecord class belongs to another
Given two subclasses of ActiveRecord::Base, how can I implement a function that checks to see if one belongs to the other?
def ClazzA < ActiveRecord::Base
belongs_to :clazz_b
end
def ClazzB < ActiveRecord::Base
has_many :clazz_a
end
def…
maxenglander
- 3,991
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4
votes
1 answer
Multiple entries in a :has_many through association
I need some help with a rails development that I'm working on, using rails 3.
This app was given to me a few months ago just after it's inception and I have since become rather fond of Ruby.
I have a set of Projects that can have resources assigned…
David Corbino
- 43
- 4
4
votes
1 answer
Rails Rich Association - Overwriting to association model
Suppose we have three models PATIENTS, NURSES, and their association model APPOINTMENTS.
This week all patients have to meet with their nurses.
A patient has many nurses, and a nurse has many patients. Likewise, a patient has many appointments, but…
Ian
- 369
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4
votes
3 answers
Rails associtating three models
I have the following models in my rails application
class User < ApplicationRecord
end
class Group < ApplicationRecord
end
class Role < ApplicationRecord
end
Every Group has_many User with different Role. For example Group-1 have User - A with…
Karthik Muthu
- 135
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- 13
4
votes
2 answers
Composition is not "Composition"
Composition: A class can have references to objects of other classes as members. This is called composition and is sometimes referred to as a has-a relationship.
By Deitel P.J., Deitel H.M. - Java How to Program 9th Edition.
This viewpoint is…
atorres
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4
votes
1 answer
Rails Polymorphic associations with name space
I want to save different results(default and manual), each result can have a reason. Thought that this would be a good place for a polymorphic association. The Models are namespaced however and this is prooving to be tricker than anticipated.…
legendary_rob
- 12,792
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4
votes
1 answer
Rails: Association between Category, Subcategory, and Lawyer
I have a vast list of Lawyers, Categories, and Subcategories.
Hint (so you could have a clue if my associations are okay)
On Categories Table, I do not want to see a column on Categories Table referencing Subcategories.
On Subcategories Table, I…
Afolabi Olaoluwa
- 1,898
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4
votes
1 answer
List all associations as links in active admin
Is it possible in active admin to list all of the has_many associations of my record as links?
The code should look something like:
column "belongs to" do |b|
b.associations.map { |a| link_to(a.name, admin_association_path(a) }
end
But this…
azrosen92
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