active-record-associations

Prevent N+1 queries in Rails by applying eager loading strategies like `includes`, `preload`, or `eager_load` when fetching associated Active Record models. This ensures associations are loaded in a minimal number of database queries rather than one per record.

You need polymorphic associations in Active Record when a single model belongs to multiple different models. This allows a model to belong_to more than one other type of model on a single association, avoiding the need for multiple specialized foreign keys.

Set up a `has_many :through` association in Rails by creating a join model and defining `belongs_to` on both related models. This establishes a many-to-many connection, allowing you to work directly with the intermediate association.

Use `dependent:` options like `:destroy` or `:delete_all` on your Active Record associations to prevent orphaned records. This ensures that when a parent record is deleted, its associated child records are also automatically removed from the database.

Yes, you can use counter caches with Rails associations to efficiently track the number of associated records. By adding a counter cache column, Active Record automatically maintains the count, avoiding expensive database count queries on the fly.