diff options
Diffstat (limited to 'activerecord/lib/active_record/associations')
| -rw-r--r-- | activerecord/lib/active_record/associations/has_many_through_association.rb | 2 | ||||
| -rw-r--r-- | activerecord/lib/active_record/associations/nested_has_many_through.rb | 156 |
2 files changed, 158 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb index 97883d8393..964c381c0d 100644 --- a/activerecord/lib/active_record/associations/has_many_through_association.rb +++ b/activerecord/lib/active_record/associations/has_many_through_association.rb @@ -1,4 +1,5 @@ require "active_record/associations/through_association_scope" +require "active_record/associations/nested_has_many_through" require 'active_support/core_ext/object/blank' module ActiveRecord @@ -6,6 +7,7 @@ module ActiveRecord module Associations class HasManyThroughAssociation < HasManyAssociation #:nodoc: include ThroughAssociationScope + include NestedHasManyThrough alias_method :new, :build diff --git a/activerecord/lib/active_record/associations/nested_has_many_through.rb b/activerecord/lib/active_record/associations/nested_has_many_through.rb new file mode 100644 index 0000000000..2d03b81128 --- /dev/null +++ b/activerecord/lib/active_record/associations/nested_has_many_through.rb @@ -0,0 +1,156 @@ +module ActiveRecord + module Associations + module NestedHasManyThrough + def self.included(klass) + klass.alias_method_chain :construct_conditions, :nesting + klass.alias_method_chain :construct_joins, :nesting + end + + def construct_joins_with_nesting(custom_joins = nil) + if nested? + @nested_join_attributes ||= construct_nested_join_attributes + "#{construct_nested_join_attributes[:joins]} #{@reflection.options[:joins]} #{custom_joins}" + else + construct_joins_without_nesting(custom_joins) + end + end + + def construct_conditions_with_nesting + if nested? + @nested_join_attributes ||= construct_nested_join_attributes + if @reflection.through_reflection && @reflection.through_reflection.macro == :belongs_to + "#{@nested_join_attributes[:remote_key]} = #{belongs_to_quoted_key} #{@nested_join_attributes[:conditions]}" + else + "#{@nested_join_attributes[:remote_key]} = #{@owner.quoted_id} #{@nested_join_attributes[:conditions]}" + end + else + construct_conditions_without_nesting + end + end + + protected + + # Given any belongs_to or has_many (including has_many :through) association, + # return the essential components of a join corresponding to that association, namely: + # + # * <tt>:joins</tt>: any additional joins required to get from the association's table + # (reflection.table_name) to the table that's actually joining to the active record's table + # * <tt>:remote_key</tt>: the name of the key in the join table (qualified by table name) which will join + # to a field of the active record's table + # * <tt>:local_key</tt>: the name of the key in the local table (not qualified by table name) which will + # take part in the join + # * <tt>:conditions</tt>: any additional conditions (e.g. filtering by type for a polymorphic association, + # or a :conditions clause explicitly given in the association), including a leading AND + def construct_nested_join_attributes(reflection = @reflection, association_class = reflection.klass, table_ids = {association_class.table_name => 1}) + if (reflection.macro == :has_many || reflection.macro == :has_one) && reflection.through_reflection + construct_has_many_through_attributes(reflection, table_ids) + else + construct_has_many_or_belongs_to_attributes(reflection, association_class, table_ids) + end + end + + def construct_has_many_through_attributes(reflection, table_ids) + # Construct the join components of the source association, so that we have a path from + # the eventual target table of the association up to the table named in :through, and + # all tables involved are allocated table IDs. + source_attrs = construct_nested_join_attributes(reflection.source_reflection, reflection.klass, table_ids) + + # Determine the alias of the :through table; this will be the last table assigned + # when constructing the source join components above. + through_table_alias = through_table_name = reflection.through_reflection.table_name + through_table_alias += "_#{table_ids[through_table_name]}" unless table_ids[through_table_name] == 1 + + # Construct the join components of the through association, so that we have a path to + # the active record's table. + through_attrs = construct_nested_join_attributes(reflection.through_reflection, reflection.through_reflection.klass, table_ids) + + # Any subsequent joins / filters on owner attributes will act on the through association, + # so that's what we return for the conditions/keys of the overall association. + conditions = through_attrs[:conditions] + conditions += " AND #{interpolate_sql(reflection.klass.send(:sanitize_sql, reflection.options[:conditions]))}" if reflection.options[:conditions] + + { + :joins => "%s INNER JOIN %s ON ( %s = %s.%s %s) %s %s" % [ + source_attrs[:joins], + through_table_name == through_table_alias ? through_table_name : "#{through_table_name} #{through_table_alias}", + source_attrs[:remote_key], + through_table_alias, source_attrs[:local_key], + source_attrs[:conditions], + through_attrs[:joins], + reflection.options[:joins] + ], + :remote_key => through_attrs[:remote_key], + :local_key => through_attrs[:local_key], + :conditions => conditions + } + end + + # reflection is not has_many :through; it's a standard has_many / belongs_to instead + # TODO: see if we can defer to rails code here a bit more + def construct_has_many_or_belongs_to_attributes(reflection, association_class, table_ids) + # Determine the alias used for remote_table_name, if any. In all cases this will already + # have been assigned an ID in table_ids (either through being involved in a previous join, + # or - if it's the first table in the query - as the default value of table_ids) + remote_table_alias = remote_table_name = association_class.table_name + remote_table_alias += "_#{table_ids[remote_table_name]}" unless table_ids[remote_table_name] == 1 + + # Assign a new alias for the local table. + local_table_alias = local_table_name = reflection.active_record.table_name + if table_ids[local_table_name] + table_id = table_ids[local_table_name] += 1 + local_table_alias += "_#{table_id}" + else + table_ids[local_table_name] = 1 + end + + conditions = '' + # Add type_condition, if applicable + conditions += " AND #{association_class.send(:type_condition).to_sql}" if association_class.finder_needs_type_condition? + # Add custom conditions + conditions += " AND (#{interpolate_sql(association_class.send(:sanitize_sql, reflection.options[:conditions]))})" if reflection.options[:conditions] + + if reflection.macro == :belongs_to + if reflection.options[:polymorphic] + conditions += " AND #{local_table_alias}.#{reflection.options[:foreign_type]} = #{reflection.active_record.quote_value(association_class.base_class.name.to_s)}" + end + { + :joins => reflection.options[:joins], + :remote_key => "#{remote_table_alias}.#{association_class.primary_key}", + :local_key => reflection.primary_key_name, + :conditions => conditions + } + else + # Association is has_many (without :through) + if reflection.options[:as] + conditions += " AND #{remote_table_alias}.#{reflection.options[:as]}_type = #{reflection.active_record.quote_value(reflection.active_record.base_class.name.to_s)}" + end + { + :joins => "#{reflection.options[:joins]}", + :remote_key => "#{remote_table_alias}.#{reflection.primary_key_name}", + :local_key => reflection.klass.primary_key, + :conditions => conditions + } + end + end + + def belongs_to_quoted_key + attribute = @reflection.through_reflection.primary_key_name + column = @owner.column_for_attribute attribute + + @owner.send(:quote_value, @owner.send(attribute), column) + end + + def nested? + through_source_reflection? || through_through_reflection? + end + + def through_source_reflection? + @reflection.source_reflection && @reflection.source_reflection.options[:through] + end + + def through_through_reflection? + @reflection.through_reflection && @reflection.through_reflection.options[:through] + end + end + end +end |