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Questions tagged [has-and-belongs-to-many]

A has_many :through association set up a many-to-many connection with another model.

In Ruby on Rails, a has_many :through association is often used to set up a many-to-many connection with another model. This association indicates that the declaring model can be matched with zero or more instances of another model by proceeding through a third model.

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Rails: Find rows without connection in HABTM relation

I have two models, Users and Leads connected with HABTM relation: class Lead < ActiveRecord::Base has_and_belongs_to_many :users end class User < ActiveRecord::Base has_and_belongs_to_many :leads end How can I now get only those Leads which…
Kerozu
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How can I delete an entry from a HABTM join table in rails?

Through many iterations of testing, I just noticed that my join table that represents a HABTM relationship between two models isn't removing entries when instances of these models get deleted. Do I need to do something special when removing an…
James
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Rails - how to order a model by its has many association?

I have two models: #Product class Product < ActiveRecord::Base has_and_belongs_to_many :categories attr_accessible :name ... end #Category class Category < ActiveRecord::Base has_and_belongs_to_many :products, :order => "name ASC" …
Kulgar
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HABTM mongoid following/follower

Mongoid ships with .push on a habtm, which sets a habtm relationship in both directions. Although delete will #delete an associated record, there's no documented way to delete only a relationship that I have seen. Is there a better way of doing…
Peter Ehrlich
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ActiveAdmin - implement HABTM / multidimensional array in DSL

In my application everything works fine, but in my Active Admin backend I don't get my user roles displayed on screen. I have two models "User" and "Roles": class Role < ActiveRecord::Base has_and_belongs_to_many :users, :join_table =>…
user930328
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Implementing tags in Rails: How to reference multiple items with one tag?

I'm writing a blog engine in rails, and have set up a tag model and a post model which have a have_and_belongs_to_many relationship. Tag addition works fine, the problem comes when looking for all posts with a specific tag: If I add tag "test" to…
Chazu
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Laravel Jensseger Mongodb belongsToMany additional fields

the documentation says "The belongsToMany relation will not use a pivot "table", but will push id's to a related_ids attribute instead. This makes the second parameter for the belongsToMany method useless. If you want to define custom keys for your…
Luigi De Francisci
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MySQL INTERSECT via joins table?

So essentially I have two tables, containing URLS and TAGS, with a has-and-belongs-to-many relationship between the two via a joins tables TAGS_URLS. A simple query to find URL's by tags would be: SELECT urls.id FROM urls INNER JOIN tags_urls ON…
Steve C.
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CakePHP - problem with HABTM paginate query

Tables restaurants cuisines cuisines_restaurants Both restaurant and cuisine model are set up to HABTM each other. I'm trying to get a paginated list of restaurants where Cuisine.name = 'italian' (example), but keep getting this error: 1054:…
Dave
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Cake HABTM Query, Order By Rand()

I'm aware that Cake HABTM associations are tricky at the best of times, but I seem to be making life even harder for myself... If I want to return a random Item from the db, I can do it as follows in the Item model: $random = $this->find('first',…
thesunneversets
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Rails: How to observe join records that don't actually have a Model?

Is it possible, using an Observer, to observe the creation of JOIN records? For example, you have a User Model that has_and_belongs_to_many Book Models. Is it possible to monitor books_users records as they are created or deleted or must I have a…
David
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Rails has_many through cannot save in nested form due to id = null

Using Rails 4.1.13 and Ruby 2.0.0 (although I had the same problem with Ralis 4.0 and Ruby 1.9.3. I have read numerous articles about this particular issue and cannot understand why my solution (which seems exactly like this) does not work, so…
Christoffer
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Rails 4 scope on HABTM association

I'm a rails newbie and I created a scope on a HABTM association, but I still think it looks unnatural, not elegant, so I think there must be a better way of doing it. Could anyone advise me if there is such better way? I've seen other posts where…
Donato Azevedo
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Rails 4.2 saving has_and_belongs_to_many association Ids

I have the following bit of code that is working fine with Rails 4.1 with protected_attributes gem (I didn't have my code moved to strong_parameters yet) models/employee.rb class Employee has_and_belongs_to_many :skills attr_accessible…
thanikkal
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Rails Associations, habtm? Polymorphic? Both?

In my Rails app I have three models, Projects, BlogPosts and Images. Projects and BlogPosts can have many linked images and an image can be linked to a Project, a BlogPost or both. What is the best way of setting up the associations to make this…
philnash
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