Methods
D
E
Instance Protected methods
default_scope(scope = {})

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
    # File activerecord/lib/active_record/scoping/default.rb, line 95
95:         def default_scope(scope = {})
96:           scope = Proc.new if block_given?
97:           self.default_scopes = default_scopes + [scope]
98:         end
evaluate_default_scope()

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 scope...

     # File activerecord/lib/active_record/scoping/default.rb, line 128
128:         def evaluate_default_scope
129:           return if ignore_default_scope?
130: 
131:           begin
132:             self.ignore_default_scope = true
133:             yield
134:           ensure
135:             self.ignore_default_scope = false
136:           end
137:         end