Use this macro in your model to set a default scope for all operations on the model.
class Article < ActiveRecord::Base default_scope where(:published => true) end Article.all # => SELECT * FROM articles WHERE published = true
The default_scope
is also applied while creating/building a
record. It is not applied while updating a record.
Article.new.published # => true Article.create.published # => true
You can also use default_scope
with a block, in order to have
it lazily evaluated:
class Article < ActiveRecord::Base default_scope { where(:published_at => Time.now - 1.week) } end
(You can also pass any object which responds to call
to the
default_scope
macro, and it will be called when building the
default scope.)
If you use multiple default_scope
declarations in your model
then they will be merged together:
class Article < ActiveRecord::Base default_scope where(:published => true) default_scope where(:rating => 'G') end Article.all # => SELECT * FROM articles WHERE published = true AND rating = 'G'
This is also the case with inheritance and module includes where the parent
or module defines a default_scope
and the child or including
class defines a second one.
If you need to do more complex things with a default scope, you can alternatively define it as a class method:
class Article < ActiveRecord::Base def self.default_scope # Should return a scope, you can call 'super' here etc. end end
The ignore_default_scope flag is used to prevent an infinite recursion situation where a default scope references a scope which has a default scope which references a scopeā¦