diff options
Diffstat (limited to 'activerecord/lib/active_record/associations/through_association.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations/through_association.rb | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/associations/through_association.rb b/activerecord/lib/active_record/associations/through_association.rb new file mode 100644 index 0000000000..57718285f8 --- /dev/null +++ b/activerecord/lib/active_record/associations/through_association.rb @@ -0,0 +1,169 @@ +module ActiveRecord + # = Active Record Through Association + module Associations + module ThroughAssociation + + def scoped + with_scope(@scope) do + @reflection.klass.scoped & + @reflection.through_reflection.klass.scoped + end + end + + def stale_target? + if @target && @reflection.through_reflection.macro == :belongs_to && defined?(@through_foreign_key) + previous_key = @through_foreign_key.to_s + current_key = @owner.send(@reflection.through_reflection.primary_key_name).to_s + + previous_key != current_key + else + false + end + end + + protected + + def construct_find_scope + { + :conditions => construct_conditions, + :joins => construct_joins, + :include => @reflection.options[:include] || @reflection.source_reflection.options[:include], + :select => construct_select, + :order => @reflection.options[:order], + :limit => @reflection.options[:limit], + :readonly => @reflection.options[:readonly] + } + end + + # This scope affects the creation of the associated records (not the join records). At the + # moment we only support creating on a :through association when the source reflection is a + # belongs_to. Thus it's not necessary to set a foreign key on the associated record(s), so + # this scope has can legitimately be empty. + def construct_create_scope + { } + end + + def aliased_through_table + name = @reflection.through_reflection.table_name + + @reflection.table_name == name ? + @reflection.through_reflection.klass.arel_table.alias(name + "_join") : + @reflection.through_reflection.klass.arel_table + end + + def construct_owner_conditions + super(aliased_through_table, @reflection.through_reflection) + end + + def construct_select + @reflection.options[:select] || + @reflection.options[:uniq] && "DISTINCT #{@reflection.quoted_table_name}.*" + end + + def construct_joins + right = aliased_through_table + left = @reflection.klass.arel_table + + conditions = [] + + if @reflection.source_reflection.macro == :belongs_to + reflection_primary_key = @reflection.source_reflection.options[:primary_key] || + @reflection.klass.primary_key + source_primary_key = @reflection.source_reflection.primary_key_name + if @reflection.options[:source_type] + column = @reflection.source_reflection.options[:foreign_type] + conditions << + right[column].eq(@reflection.options[:source_type]) + end + else + reflection_primary_key = @reflection.source_reflection.primary_key_name + source_primary_key = @reflection.source_reflection.options[:primary_key] || + @reflection.through_reflection.klass.primary_key + if @reflection.source_reflection.options[:as] + column = "#{@reflection.source_reflection.options[:as]}_type" + conditions << + left[column].eq(@reflection.through_reflection.klass.name) + end + end + + conditions << + left[reflection_primary_key].eq(right[source_primary_key]) + + right.create_join( + right, + right.create_on(right.create_and(conditions))) + end + + # Construct attributes for :through pointing to owner and associate. + def construct_join_attributes(associate) + # TODO: revisit this to allow it for deletion, supposing dependent option is supported + raise ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(@owner, @reflection) if [:has_one, :has_many].include?(@reflection.source_reflection.macro) + + join_attributes = { + @reflection.source_reflection.primary_key_name => + associate.send(@reflection.source_reflection.association_primary_key) + } + + if @reflection.options[:source_type] + join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name) + end + + if @reflection.through_reflection.options[:conditions].is_a?(Hash) + join_attributes.merge!(@reflection.through_reflection.options[:conditions]) + end + + join_attributes + end + + def conditions + @conditions = build_conditions unless defined?(@conditions) + @conditions + end + + def build_conditions + association_conditions = @reflection.options[:conditions] + through_conditions = build_through_conditions + source_conditions = @reflection.source_reflection.options[:conditions] + uses_sti = !@reflection.through_reflection.klass.descends_from_active_record? + + if association_conditions || through_conditions || source_conditions || uses_sti + all = [] + + [association_conditions, source_conditions].each do |conditions| + all << interpolate_sql(sanitize_sql(conditions)) if conditions + end + + all << through_conditions if through_conditions + all << build_sti_condition if uses_sti + + all.map { |sql| "(#{sql})" } * ' AND ' + end + end + + def build_through_conditions + conditions = @reflection.through_reflection.options[:conditions] + if conditions.is_a?(Hash) + interpolate_sql(@reflection.through_reflection.klass.send(:sanitize_sql, conditions)).gsub( + @reflection.quoted_table_name, + @reflection.through_reflection.quoted_table_name) + elsif conditions + interpolate_sql(sanitize_sql(conditions)) + end + end + + def build_sti_condition + @reflection.through_reflection.klass.send(:type_condition).to_sql + end + + alias_method :sql_conditions, :conditions + + def update_stale_state + construct_scope if stale_target? + + if @reflection.through_reflection.macro == :belongs_to + @through_foreign_key = @owner.send(@reflection.through_reflection.primary_key_name) + end + end + end + end +end |