Explain what is Polymorphic Association in Ruby on Rails?

A polymorphic association in Ruby on Rails allows a model to belong to more than one other model on a single association. It is a type of Active Record association that provides a way to associate a model with multiple other models on a single association[1][2][3].

The key aspects of polymorphic associations are:

• A model can belong to multiple models through a single association[1][2]
• It uses two columns in the database: <model>_type and <model>_id to store the associated model name and id[1][2][3]
• The <model>_type column stores the class name of the associated object[2][3]
• The <model>_id column stores the id of the associated object[2][3]
• It requires a belongs_to declaration in the model with the polymorphic: true option[1][2]

For example, consider a Review model that can be associated with both an Event and a Restaurant model. Using polymorphic associations, the Review model would have a reviewable_type and reviewable_id column to store the associated model name and id[2][3].

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