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-rw-r--r--activerecord/lib/active_record/relation/query_methods.rb96
1 files changed, 87 insertions, 9 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 3a7b245c51..c281bead0d 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -9,7 +9,8 @@ module ActiveRecord
:select_values, :group_values, :order_values, :joins_values,
:where_values, :having_values, :bind_values,
:limit_value, :offset_value, :lock_value, :readonly_value, :create_with_value,
- :from_value, :reorder_value, :reverse_order_value
+ :from_value, :reorder_value, :reverse_order_value,
+ :uniq_value
def includes(*args)
args.reject! {|a| a.blank? }
@@ -37,6 +38,35 @@ module ActiveRecord
relation
end
+ # Works in two unique ways.
+ #
+ # First: takes a block so it can be used just like Array#select.
+ #
+ # Model.scoped.select { |m| m.field == value }
+ #
+ # This will build an array of objects from the database for the scope,
+ # converting them into an array and iterating through them using Array#select.
+ #
+ # Second: Modifies the SELECT statement for the query so that only certain
+ # fields are retrieved:
+ #
+ # >> Model.select(:field)
+ # => [#<Model field:value>]
+ #
+ # Although in the above example it looks as though this method returns an
+ # array, it actually returns a relation object and can have other query
+ # methods appended to it, such as the other methods in ActiveRecord::QueryMethods.
+ #
+ # This method will also take multiple parameters:
+ #
+ # >> Model.select(:field, :other_field, :and_one_more)
+ # => [#<Model field: "value", other_field: "value", and_one_more: "value">]
+ #
+ # Any attributes that do not have fields retrieved by a select
+ # will return `nil` when the getter method for that attribute is used:
+ #
+ # >> Model.select(:field).first.other_field
+ # => nil
def select(value = Proc.new)
if block_given?
to_a.select {|*block_args| value.call(*block_args) }
@@ -147,6 +177,58 @@ module ActiveRecord
relation
end
+ # Specifies whether the records should be unique or not. For example:
+ #
+ # User.select(:name)
+ # # => Might return two records with the same name
+ #
+ # User.select(:name).uniq
+ # # => Returns 1 record per unique name
+ #
+ # User.select(:name).uniq.uniq(false)
+ # # => You can also remove the uniqueness
+ def uniq(value = true)
+ relation = clone
+ relation.uniq_value = value
+ relation
+ end
+
+ # Used to extend a scope with additional methods, either through
+ # a module or through a block provided.
+ #
+ # The object returned is a relation, which can be further extended.
+ #
+ # === Using a module
+ #
+ # module Pagination
+ # def page(number)
+ # # pagination code goes here
+ # end
+ # end
+ #
+ # scope = Model.scoped.extending(Pagination)
+ # scope.page(params[:page])
+ #
+ # You can also pass a list of modules:
+ #
+ # scope = Model.scoped.extending(Pagination, SomethingElse)
+ #
+ # === Using a block
+ #
+ # scope = Model.scoped.extending do
+ # def page(number)
+ # # pagination code goes here
+ # end
+ # end
+ # scope.page(params[:page])
+ #
+ # You can also use a block and a module list:
+ #
+ # scope = Model.scoped.extending(Pagination) do
+ # def per_page(number)
+ # # pagination code goes here
+ # end
+ # end
def extending(*modules)
modules << Module.new(&Proc.new) if block_given?
@@ -187,6 +269,7 @@ module ActiveRecord
build_select(arel, @select_values.uniq)
+ arel.distinct(@uniq_value)
arel.from(@from_value) if @from_value
arel.lock(@lock_value) if @lock_value
@@ -254,12 +337,12 @@ module ActiveRecord
association_joins = buckets['association_join'] || []
stashed_association_joins = buckets['stashed_join'] || []
- join_nodes = buckets['join_node'] || []
+ join_nodes = (buckets['join_node'] || []).uniq
string_joins = (buckets['string_join'] || []).map { |x|
x.strip
}.uniq
- join_list = custom_join_ast(manager, string_joins)
+ join_list = join_nodes + custom_join_ast(manager, string_joins)
join_dependency = ActiveRecord::Associations::JoinDependency.new(
@klass,
@@ -267,10 +350,6 @@ module ActiveRecord
join_list
)
- join_nodes.each do |join|
- join_dependency.alias_tracker.aliased_name_for(join.left.name.downcase)
- end
-
join_dependency.graft(*stashed_association_joins)
@implicit_readonly = true unless association_joins.empty? && stashed_association_joins.empty?
@@ -280,7 +359,6 @@ module ActiveRecord
association.join_to(manager)
end
- manager.join_sources.concat join_nodes.uniq
manager.join_sources.concat join_list
manager
@@ -312,7 +390,7 @@ module ActiveRecord
when String, Symbol
o.to_s.split(',').collect do |s|
s.strip!
- (s if s =~ /\(/) || s.gsub!(/\sasc\Z/i, ' DESC') || s.gsub!(/\sdesc\Z/i, ' ASC') || s.concat(' DESC')
+ s.gsub!(/\sasc\Z/i, ' DESC') || s.gsub!(/\sdesc\Z/i, ' ASC') || s.concat(' DESC')
end
else
o