Module: ActiveRecord::SpawnMethods

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In: `AssociationRelation`, `Associations::CollectionProxy`, `DisableJoinsAssociationRelation`, `Relation`
Defined in:	activerecord/lib/active_record/relation/spawn_methods.rb

Instance Method Summary

#except(*skips)

Removes from the query the condition(s) specified in skips.
#merge(other, *rest)

Merges in the conditions from other, if other is an Relation.
#only(*onlies)

Removes any condition from the query other than the one(s) specified in onlies.
#relation_with(values) private
#merge!(other, *rest) Internal use only
#spawn Internal use only

Instance Method Details

#except(*skips)

Removes from the query the condition(s) specified in skips.

Post.order('id asc').except(:order)                  # discards the order condition
Post.where('id > 10').order('id asc').except(:where) # discards the where condition but keeps the order

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 75


def except(*skips)
  relation_with values.except(*skips)
end

#merge(other, *rest)

Merges in the conditions from other, if other is an Relation. Returns an array representing the intersection of the resulting records with other, if other is an array.

Post.where(published: true).joins(:comments).merge( Comment.where(spam: false) )
# Performs a single join query with both where conditions.

recent_posts = Post.order('created_at DESC').first(5)
Post.where(published: true).merge(recent_posts)
# Returns the intersection of all published posts with the 5 most recently created posts.
# (This is just an example. You'd probably want to do this with a single query!)

Procs will be evaluated by merge:

Post.where(published: true).merge(-> { joins(:comments) })
# => Post.where(published: true).joins(:comments)

This is mainly intended for sharing common conditions between multiple associations.

For conditions that exist in both relations, those from other will take precedence. To find the intersection of two relations, use QueryMethods#and.

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 33


def merge(other, *rest)
  if other.is_a?(Array)
    records & other
  elsif other
    spawn.merge!(other, *rest)
  else
    raise ArgumentError, "invalid argument: #{other.inspect}."
  end
end

#merge!(other, *rest)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 43


def merge!(other, *rest) # :nodoc:
  options = rest.extract_options!

  if options.key?(:rewhere)
    if options[:rewhere]
      ActiveRecord.deprecator.warn(<<-MSG.squish)
        Specifying `Relation#merge(rewhere: true)` is deprecated, as that has now been
        the default since Rails 7.0. Setting the rewhere option will error in Rails 7.2
      MSG
    else
      ActiveRecord.deprecator.warn(<<-MSG.squish)
        `Relation#merge(rewhere: false)` is deprecated without replacement,
        and will be removed in Rails 7.2
      MSG
    end
  end

  if other.is_a?(Hash)
    Relation::HashMerger.new(self, other, options[:rewhere]).merge
  elsif other.is_a?(Relation)
    Relation::Merger.new(self, other, options[:rewhere]).merge
  elsif other.respond_to?(:to_proc)
    instance_exec(&other)
  else
    raise ArgumentError, "#{other.inspect} is not an ActiveRecord::Relation"
  end
end

#only(*onlies)

Removes any condition from the query other than the one(s) specified in onlies.

Post.order('id asc').only(:where)         # discards the order condition
Post.order('id asc').only(:where, :order) # uses the specified order

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 83


def only(*onlies)
  relation_with values.slice(*onlies)
end

#relation_with(values) (private)

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 88


def relation_with(values)
  result = spawn
  result.instance_variable_set(:@values, values)
  result
end

#spawn

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/relation/spawn_methods.rb', line 9


def spawn # :nodoc:
  already_in_scope?(klass.scope_registry) ? klass.all : clone
end