diff options
| -rw-r--r-- | activerecord/lib/active_record/associations/collection_proxy.rb | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb index bc310cd13e..6fd5c466f6 100644 --- a/activerecord/lib/active_record/associations/collection_proxy.rb +++ b/activerecord/lib/active_record/associations/collection_proxy.rb @@ -540,20 +540,52 @@ module ActiveRecord # has_many :pets # end # - # # This will execute: - # # SELECT COUNT(*) FROM "pets" WHERE "pets"."person_id" = ? [["person_id", 1]] # person.pets.size # => 3 + # # Executes: + # # + # # SELECT COUNT(*) + # # FROM "pets" + # # WHERE "pets"."person_id" = 1 # - # person.pets + # person.pets # This will execute a SELECT * FROM query # # => [ # # #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>, # # #<Pet id: 2, name: "Spook", person_id: 1>, # # #<Pet id: 3, name: "Choo-Choo", person_id: 1> # # ] # - # # Because the collection is already loaded, this will behave like - # <tt>collection.size</tt> and no SQL count query is executed. # person.pets.size # => 3 + # # Because the collection is already loaded, this will behave like + # # collection.size and no SQL count query is executed. + + ## + # :method: length + # + # Returns the size of the collection calling +size+ on the target. + # If the collection has been already loaded +length+ and +size+ are + # equivalent. If not and you are going to need the records anyway this + # method will take one less query because loads the collection. Otherwise + # +size+ is more efficient. + # + # class Person < ActiveRecord::Base + # has_many :pets + # end + # + # person.pets.length # => 3 + # # Executes: + # # + # # SELECT "pets".* + # # FROM "pets" + # # WHERE "pets"."person_id" = 1 + # + # # Because the collection is loaded, you can + # # call the collection without execute a query: + # person.pets + # # => [ + # # #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>, + # # #<Pet id: 2, name: "Spook", person_id: 1>, + # # #<Pet id: 3, name: "Choo-Choo", person_id: 1> + # # ] ## # :method: empty? |