In Rails, to reset associations
and clear the cache for a specific association, we can use the reset method.
This method reloads the association
and clears any cached data related to it.
class Client < ApplicationRecord
has_many :invoices
has_one :project
end
class Invoice < ApplicationRecord
belongs :client
end
class Project < ApplicationRecord
belongs :client
endclient = Client.first
client.invoices
# => returns the array of invoices. e.g: 3 invoices# Let's delete one invoice
client.invoices.first.destroy
# Let's check client invoices
client.invoices
# => it's still 3 invoices (Due to caching)# Let's reset associations and clear the cache
client.invoices.reset
# => queries the database again and this time it will show 2 invoices.Before
If we observe the above example, we reset associations
and cleared the cache on has_many associations. But for singular associations, we can not reset and clear the cache.
client.project
# => returns the project.# Let's delete the project
client.project.destroy
# Let's check the client project
client.project
# => It still shows the single project (Due to caching)# Let's reset associations and clear the cache
client.project.reset
# => NoMethodError (`method_missing': undefined method reset`)Before Rails 7.1, to reset the associations
and clear the cache, we can use the reload association method.
client.project
# => returns the project.# Let's delete the project
client.project.destroy
# Let's check the client project
client.project
# => It still shows the single project (Due to caching)# Let's reset associations and clear the cache
client.reload_project
# => queries the database again and this time it will show no project.But there is no reset method on singular associations.
After
Rails 7.1 allows resetting singular associations.
has_one and belongs_to associations now define a reset_association method on the owner model (where association is the name of the association).
This method unloads the cached associate record, if any, and causes the next access to query it from the database.
client.project
# => returns the project.# Let's delete the project
client.project.destroy
# Let's check the client project
client.project
# => it's still shows the single project (Due to caching)# Let's reset associations and clear the cache
client.reset_project
# => queries the database again and this time it will show no project.With this refined approach, we can easily reset singular associations and handle association caching.
