diff options
Diffstat (limited to 'activerecord/lib/active_record/relation')
-rw-r--r-- | activerecord/lib/active_record/relation/query_methods.rb | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index 6f49548aab..e401ed37b0 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -41,6 +41,17 @@ module ActiveRecord alias extensions extending_values + # Specify relationships to be included in the result set. For + # example: + # + # users = User.includes(:address) + # users.each do |user| + # user.address.city + # end + # + # allows you to access the +address+ attribute of the +User+ model without + # firing an additional query. This will often result in a + # performance improvement over a simple +join+ def includes(*args) args.empty? ? self : spawn.includes!(*args) end @@ -131,6 +142,18 @@ module ActiveRecord self end + # Allows to specify a group attribute: + # + # User.group(:name) + # => SELECT "users".* FROM "users" GROUP BY name + # + # Returns an array with distinct records based on the `group` attribute: + # + # User.select([:id, :name]) + # => [#<User id: 1, name: "Oscar">, #<User id: 2, name: "Oscar">, #<User id: 3, name: "Foo"> + # + # User.group(:name) + # => [#<User id: 3, name: "Foo", ...>, #<User id: 2, name: "Oscar", ...>] def group(*args) args.blank? ? self : spawn.group!(*args) end @@ -142,6 +165,16 @@ module ActiveRecord self end + # Allows to specify an order attribute: + # + # User.order('name') + # => SELECT "users".* FROM "users" ORDER BY name + # + # User.order('name DESC') + # => SELECT "users".* FROM "users" ORDER BY name DESC + # + # User.order('name DESC, email') + # => SELECT "users".* FROM "users" ORDER BY name DESC, email def order(*args) args.blank? ? self : spawn.order!(*args) end |