Rails one-to-one relationship. It is basically a one-to-one relationship between a user and a car. That implies the fact that if he creates a car assigned to him, he won't be able to create the second.Similarly, does Association have one rails?
belongs_to means that the foreign key is in the table for this class. So belongs_to can ONLY go in the class that holds the foreign key. has_one means that there is a foreign key in another table that references this class. So has_one can ONLY go in a class that is referenced by a column in another table.
Beside above, what is an ActiveRecord relation? The Relation Class. Having queries return an ActiveRecord::Relation object allows us to chain queries together and this Relation class is at the heart of the new query syntax. This class contains the methods that we use in the new query syntax: includes , select , group , order , joins and so on.
Considering this, what is dependent destroy rails?
If you set the :dependent option to: :destroy, when the object is destroyed, destroy will be called on its associated objects. :delete, when the object is destroyed, all its associated objects will be deleted directly from the database without calling their destroy method.
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 counter cache?
Instead of counting the associated records in the database every time the page loads, ActiveRecord's counter caching feature allows storing the counter and updating it every time an associated object is created or removed. In this episode of AppSignal Academy, we'll learn all about caching counters in ActiveRecord.What is scopes how should you use it?
Scopes are custom queries that you define inside your Rails models with the scope method. Every scope takes two arguments: A name, which you use to call this scope in your code. A lambda, which implements the query.Is active record an ORM?
Active Record is an implementation of the object-relational mapping (ORM) pattern by the same name described by Martin Fowler: "An object that wraps a row in a database table or view, encapsulates the database access, and adds domain logic on that data."What is Ruby on Rails framework?
Website. rubyonrails.org. Ruby on Rails, or Rails, is a server-side web application framework written in Ruby under the MIT License. Rails is a model–view–controller (MVC) framework, providing default structures for a database, a web service, and web pages.What is polymorphism in Ruby?
Polymorphism in Ruby. So Polymorphism is a method where one is able to execute the same method using different objects. In polymorphism, we can obtain different results using the same function by passing different input objects.What is single table inheritance in rails?
What is Single Table Inheritance ? Single Table Inheritance is, as the name suggests it, a way to add inheritance to your models. STI lets you save different models inheriting from the same model inside a single table. For example, let's say you have an employee model. 
