method
merge
v6.1.3.1 -
Show latest stable
-
1 note -
Class: ActiveRecord::SpawnMethods
- 1.0.0
- 1.1.6
- 1.2.6
- 2.0.3
- 2.1.0
- 2.2.1
- 2.3.8
- 3.0.0 (0)
- 3.0.9 (0)
- 3.1.0 (0)
- 3.2.1 (0)
- 3.2.8 (0)
- 3.2.13 (0)
- 4.0.2 (38)
- 4.1.8 (0)
- 4.2.1 (0)
- 4.2.7 (0)
- 4.2.9 (0)
- 5.0.0.1 (0)
- 5.1.7 (0)
- 5.2.3 (0)
- 6.0.0 (0)
- 6.1.3.1 (0)
- 6.1.7.7 (0)
- 7.0.0 (0)
- 7.1.3.2 (7)
- 7.1.3.4 (0)
- What's this?
merge(other, *rest)
public
Merges in the conditions from other, if other is an ActiveRecord::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.
Register or
log in
to add new notes.
noniq -
March 27, 2012
4 thanks
Makes it possible to use a scope through an association
This is a very useful method if you want to to use a scope through an association:
class Book < ActiveRecord::Base scope :available, where(:available => true) end class Author < ActiveRecord::Base has_many :books scope :with_available_books, joins(:books).merge(Book.available) end # Return all authors with at least one available book: Author.with_available_books
See http://asciicasts.com/episodes/215-advanced-queries-in-rails-3 for more info.