diff options
Diffstat (limited to 'activerecord/lib/active_record/relation/query_methods.rb')
| -rw-r--r-- | activerecord/lib/active_record/relation/query_methods.rb | 74 |
1 files changed, 67 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index 1654ae1eac..670ba0987d 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -37,6 +37,35 @@ 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 +176,42 @@ module ActiveRecord 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? @@ -254,12 +319,12 @@ 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 +332,6 @@ 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 +341,6 @@ module ActiveRecord association.join_to(manager) end - manager.join_sources.concat join_nodes.uniq manager.join_sources.concat join_list manager |