What is scope?

Scopes are custom queries written in the model used for retrieving and querying objects.

How to use scope in ruby on rails?

A scope takes name and lambda

scope :admin, → {where(is_admin: true)}

How to call this scope

User.admin

How to call scope with argument

scope :created between, -> (from, to) {
where(
"created_at > ? AND created_at < ?", from, to
)}
Invoice.created between(test, today)

What is Default Scope.

A default scope gets automatically applied whenever you access the model. Be careful when this is used.

default_scope { where(active: true }
# returns only active users User.all

What is Unscoped in ruby on rails?.

If you want to remove all the previously applied scopes from the model, use unscoped.

scope :active, → {where(active: true)}
# returns all users User.active.unscoped

Advantages of scopes in ruby on rails.

Scope will always return Activerecord::Relation object.

1. This helps in method chaining.
2. It is a great way to keep the model DRY.
3. Scope looks cleaner.
4. Make application faster