How to destroy association in Rails?

1 Answer. In a has_and_belongs_to_many association you can either use delete_all or destroy_all . In a has_many association you should consider using delete_all because it deletes records following the :dependent strategy (it nullifys foreign keys by default) instead of destroy_all which destroys associated records.

What is Rails association?

In Rails, an association is a connection between two Active Record models. Why do we need associations between models? Because they make common operations simpler and easier in your code. For example, consider a simple Rails application that includes a model for authors and a model for books.

What does dependent destroy mean Rails?

dependent: :destroy Rails, when attempting to destroy an instance of the Parent, will also iteratively go through each child of the parent calling destroy on the child. The benefit of this is that any callbacks and validation on those children are given their day in the sun.

What is the difference between Has_one and Belongs_to?

They essentially do the same thing, the only difference is what side of the relationship you are on. If a User has a Profile , then in the User class you’d have has_one :profile and in the Profile class you’d have belongs_to :user .

What is Rails Active Record?

Rails Active Records provide an interface and binding between the tables in a relational database and the Ruby program code that manipulates database records. Each Active Record object has CRUD (Create, Read, Update, and Delete) methods for database access.

What is polymorphic association in Rails?

In Ruby on Rails, a polymorphic association is an Active Record association that can connect a model to multiple other models. For example, we can use a single association to connect the Review model with the Event and Restaurant models, allowing us to connect a review with either an event or a restaurant.

What is the difference between dependent => destroy and dependent => Delete_all in rails?

:Dependent possible options: :destroy causes all the associated objects to also be destroyed. :delete_all causes all the associated objects to be deleted directly from the database (so callbacks will not be executed).

Does laravel have one or belongs?

The main difference is which side of the relationship holds the relationship’s foreign key. The model that calls $this->belongsTo() is the owned model in one-to-one and many-to-one relationships and holds the key to the owning model.

Can you use ActiveRecord without rails?

One of the primary aspects of ActiveRecord is that there is very little to no configuration needed. It follow convention over configuration. ActiveRecord is commonly used with the Ruby-on-Rails framework but you can use it with Sinatra or without any web framework if desired.

What is an ActiveRecord object?

In Active Record, objects carry both persistent data and behavior which operates on that data. Active Record takes the opinion that ensuring data access logic as part of the object will educate users of that object on how to write to and read from the database.