diff options
31 files changed, 1200 insertions, 1083 deletions
diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb index 0777f85869..59cf42a377 100644 --- a/activerecord/lib/active_record.rb +++ b/activerecord/lib/active_record.rb @@ -43,7 +43,6 @@ module ActiveRecord autoload :ConnectionNotEstablished, 'active_record/errors' autoload :Aggregations - autoload :AssociationPreload autoload :Associations autoload :AttributeMethods autoload :AutosaveAssociation diff --git a/activerecord/lib/active_record/association_preload.rb b/activerecord/lib/active_record/association_preload.rb deleted file mode 100644 index a34a73cf5d..0000000000 --- a/activerecord/lib/active_record/association_preload.rb +++ /dev/null @@ -1,433 +0,0 @@ -require 'active_support/core_ext/array/wrap' -require 'active_support/core_ext/enumerable' - -module ActiveRecord - # See ActiveRecord::AssociationPreload::ClassMethods for documentation. - module AssociationPreload #:nodoc: - extend ActiveSupport::Concern - - # Implements the details of eager loading of Active Record associations. - # Application developers should not use this module directly. - # - # <tt>ActiveRecord::Base</tt> is extended with this module. The source code in - # <tt>ActiveRecord::Base</tt> references methods defined in this module. - # - # Note that 'eager loading' and 'preloading' are actually the same thing. - # However, there are two different eager loading strategies. - # - # The first one is by using table joins. This was only strategy available - # prior to Rails 2.1. Suppose that you have an Author model with columns - # 'name' and 'age', and a Book model with columns 'name' and 'sales'. Using - # this strategy, Active Record would try to retrieve all data for an author - # and all of its books via a single query: - # - # SELECT * FROM authors - # LEFT OUTER JOIN books ON authors.id = books.id - # WHERE authors.name = 'Ken Akamatsu' - # - # However, this could result in many rows that contain redundant data. After - # having received the first row, we already have enough data to instantiate - # the Author object. In all subsequent rows, only the data for the joined - # 'books' table is useful; the joined 'authors' data is just redundant, and - # processing this redundant data takes memory and CPU time. The problem - # quickly becomes worse and worse as the level of eager loading increases - # (i.e. if Active Record is to eager load the associations' associations as - # well). - # - # The second strategy is to use multiple database queries, one for each - # level of association. Since Rails 2.1, this is the default strategy. In - # situations where a table join is necessary (e.g. when the +:conditions+ - # option references an association's column), it will fallback to the table - # join strategy. - # - # See also ActiveRecord::Associations::ClassMethods, which explains eager - # loading in a more high-level (application developer-friendly) manner. - module ClassMethods - protected - - # Eager loads the named associations for the given Active Record record(s). - # - # In this description, 'association name' shall refer to the name passed - # to an association creation method. For example, a model that specifies - # <tt>belongs_to :author</tt>, <tt>has_many :buyers</tt> has association - # names +:author+ and +:buyers+. - # - # == Parameters - # +records+ is an array of ActiveRecord::Base. This array needs not be flat, - # i.e. +records+ itself may also contain arrays of records. In any case, - # +preload_associations+ will preload the all associations records by - # flattening +records+. - # - # +associations+ specifies one or more associations that you want to - # preload. It may be: - # - a Symbol or a String which specifies a single association name. For - # example, specifying +:books+ allows this method to preload all books - # for an Author. - # - an Array which specifies multiple association names. This array - # is processed recursively. For example, specifying <tt>[:avatar, :books]</tt> - # allows this method to preload an author's avatar as well as all of his - # books. - # - a Hash which specifies multiple association names, as well as - # association names for the to-be-preloaded association objects. For - # example, specifying <tt>{ :author => :avatar }</tt> will preload a - # book's author, as well as that author's avatar. - # - # +:associations+ has the same format as the +:include+ option for - # <tt>ActiveRecord::Base.find</tt>. So +associations+ could look like this: - # - # :books - # [ :books, :author ] - # { :author => :avatar } - # [ :books, { :author => :avatar } ] - # - # +preload_options+ contains options that will be passed to ActiveRecord::Base#find - # (which is called under the hood for preloading records). But it is passed - # only one level deep in the +associations+ argument, i.e. it's not passed - # to the child associations when +associations+ is a Hash. - def preload_associations(records, associations, preload_options={}) - records = Array.wrap(records).compact.uniq - return if records.empty? - case associations - when Array then associations.each {|association| preload_associations(records, association, preload_options)} - when Symbol, String then preload_one_association(records, associations.to_sym, preload_options) - when Hash then - associations.each do |parent, child| - raise "parent must be an association name" unless parent.is_a?(String) || parent.is_a?(Symbol) - preload_associations(records, parent, preload_options) - reflection = reflections[parent] - parents = records.sum { |record| Array.wrap(record.send(reflection.name)) } - unless parents.empty? - parents.first.class.preload_associations(parents, child) - end - end - end - end - - private - - # Preloads a specific named association for the given records. This is - # called by +preload_associations+ as its base case. - def preload_one_association(records, association, preload_options={}) - class_to_reflection = {} - # Not all records have the same class, so group then preload - # group on the reflection itself so that if various subclass share the same association then - # we do not split them unnecessarily - records.group_by { |record| class_to_reflection[record.class] ||= record.class.reflections[association]}.each do |reflection, _records| - raise ConfigurationError, "Association named '#{ association }' was not found; perhaps you misspelled it?" unless reflection - - # 'reflection.macro' can return 'belongs_to', 'has_many', etc. Thus, - # the following could call 'preload_belongs_to_association', - # 'preload_has_many_association', etc. - send("preload_#{reflection.macro}_association", _records, reflection, preload_options) - end - end - - def add_preloaded_records_to_collection(parent_records, reflection_name, associated_record) - parent_records.each do |parent_record| - association = parent_record.association(reflection_name) - association.loaded! - association.target.concat(Array.wrap(associated_record)) - association.set_inverse_instance(associated_record) - end - end - - def add_preloaded_record_to_collection(parent_records, reflection_name, associated_record) - parent_records.each do |parent_record| - parent_record.association(reflection_name).target = associated_record - end - end - - def set_association_collection_records(id_to_parent_map, reflection_name, associated_records, key) - associated_records.each do |associated_record| - parent_records = id_to_parent_map[associated_record[key].to_s] - add_preloaded_records_to_collection(parent_records, reflection_name, associated_record) - end - end - - def set_association_single_records(id_to_record_map, reflection_name, associated_records, key) - seen_keys = {} - associated_records.each do |associated_record| - seen_key = associated_record[key].to_s - - #this is a has_one or belongs_to: there should only be one record. - #Unfortunately we can't (in portable way) ask the database for - #'all records where foo_id in (x,y,z), but please - # only one row per distinct foo_id' so this where we enforce that - next if seen_keys.key? seen_key - - seen_keys[seen_key] = true - mapped_records = id_to_record_map[seen_key] - mapped_records.each do |mapped_record| - association_proxy = mapped_record.association(reflection_name) - association_proxy.target = associated_record - association_proxy.send(:set_inverse_instance, associated_record) - end - end - - id_to_record_map.each do |id, records| - next if seen_keys.include?(id) - add_preloaded_record_to_collection(records, reflection_name, nil) - end - end - - # Given a collection of Active Record objects, constructs a Hash which maps - # the objects' IDs to the relevant objects. Returns a 2-tuple - # <tt>(id_to_record_map, ids)</tt> where +id_to_record_map+ is the Hash, - # and +ids+ is an Array of record IDs. - def construct_id_map(records, primary_key=nil) - records.group_by do |record| - primary_key ||= record.class.primary_key - record[primary_key].to_s - end - end - - def preload_has_and_belongs_to_many_association(records, reflection, preload_options={}) - - left = reflection.klass.arel_table - - id_to_record_map = construct_id_map(records) - - records.each { |record| record.association(reflection.name).loaded! } - options = reflection.options - - right = Arel::Table.new(options[:join_table]).alias('t0') - - join_condition = left[reflection.klass.primary_key].eq( - right[reflection.association_foreign_key]) - - join = left.create_join(right, left.create_on(join_condition)) - select = [ - # FIXME: options[:select] is always nil in the tests. Do we really - # need it? - options[:select] || left[Arel.star], - right[reflection.foreign_key].as( - Arel.sql('the_parent_record_id')) - ] - - associated_records_proxy = reflection.klass.unscoped. - includes(options[:include]). - order(options[:order]) - - associated_records_proxy.joins_values = [join] - associated_records_proxy.select_values = select - - custom_conditions = append_conditions(reflection, preload_options) - - klass = associated_records_proxy.klass - - associated_records(id_to_record_map.keys) { |some_ids| - method = in_or_equal(some_ids) - conditions = right.create_and( - [right[reflection.foreign_key].send(*method)] + - custom_conditions) - - relation = associated_records_proxy.where(conditions) - klass.connection.select_all(relation.arel.to_sql, 'SQL', relation.bind_values) - }.map! { |row| - parent_records = id_to_record_map[row['the_parent_record_id'].to_s] - associated_record = klass.instantiate row - add_preloaded_records_to_collection( - parent_records, reflection.name, associated_record) - associated_record - } - end - - def preload_has_one_association(records, reflection, preload_options={}) - return if records.first.association(reflection.name).loaded? - id_to_record_map = construct_id_map(records, reflection.options[:primary_key]) - options = reflection.options - - add_preloaded_record_to_collection(records, reflection.name, nil) - - if options[:through] - through_records = preload_through_records(records, reflection, options[:through]) - - unless through_records.empty? - through_reflection = reflections[options[:through]] - through_primary_key = through_reflection.foreign_key - source = reflection.source_reflection.name - through_records.first.class.preload_associations(through_records, source) - if through_reflection.macro == :belongs_to - id_to_record_map = construct_id_map(records, through_primary_key) - through_primary_key = through_reflection.klass.primary_key - end - - through_records.each do |through_record| - add_preloaded_record_to_collection(id_to_record_map[through_record[through_primary_key].to_s], - reflection.name, through_record.send(source)) - end - end - else - set_association_single_records(id_to_record_map, reflection.name, find_associated_records(id_to_record_map.keys, reflection, preload_options), reflection.foreign_key) - end - end - - def preload_has_many_association(records, reflection, preload_options={}) - return if records.first.send(reflection.name).loaded? - options = reflection.options - - foreign_key = reflection.through_reflection_foreign_key - id_to_record_map = construct_id_map(records, foreign_key || reflection.options[:primary_key]) - records.each { |record| record.association(reflection.name).loaded! } - - if options[:through] - through_records = preload_through_records(records, reflection, options[:through]) - unless through_records.empty? - source = reflection.source_reflection.name - through_records.first.class.preload_associations(through_records, source, options) - through_records.each do |through_record| - through_record_id = through_record[reflection.through_reflection_primary_key].to_s - add_preloaded_records_to_collection(id_to_record_map[through_record_id], reflection.name, through_record.send(source)) - end - records.each { |record| record.send(reflection.name).target.uniq! } if options[:uniq] - end - - else - set_association_collection_records(id_to_record_map, reflection.name, find_associated_records(id_to_record_map.keys, reflection, preload_options), - reflection.foreign_key) - end - end - - def preload_through_records(records, reflection, through_association) - if reflection.options[:source_type] - interface = reflection.source_reflection.foreign_type - preload_options = {:conditions => ["#{connection.quote_column_name interface} = ?", reflection.options[:source_type]]} - - records.compact! - records.first.class.preload_associations(records, through_association, preload_options) - - # Dont cache the association - we would only be caching a subset - records.map { |record| - proxy = record.association(through_association) - - if proxy.respond_to?(:target) - Array.wrap(proxy.target).tap { proxy.reset } - else # this is a has_one :through reflection - [proxy].compact - end - }.flatten(1) - else - options = {} - options[:include] = reflection.options[:include] || reflection.options[:source] if reflection.options[:conditions] - options[:order] = reflection.options[:order] - options[:conditions] = reflection.options[:conditions] - records.first.class.preload_associations(records, through_association, options) - - records.map { |record| - Array.wrap(record.send(through_association)) - }.flatten(1) - end - end - - def preload_belongs_to_association(records, reflection, preload_options={}) - return if records.first.association(reflection.name).loaded? - options = reflection.options - - klasses_and_ids = {} - - if options[:polymorphic] - # Construct a mapping from klass to a list of ids to load and a mapping of those ids back - # to their parent_records - records.each do |record| - if klass = record.send(reflection.foreign_type) - klass_id = record.send(reflection.foreign_key) - if klass_id - id_map = klasses_and_ids[klass.constantize] ||= {} - (id_map[klass_id.to_s] ||= []) << record - end - end - end - else - id_map = records.group_by do |record| - key = record.send(reflection.foreign_key) - key && key.to_s - end - klasses_and_ids[reflection.klass] = id_map unless id_map.empty? - end - - klasses_and_ids.each do |klass, _id_map| - primary_key = (reflection.options[:primary_key] || klass.primary_key).to_s - keys = _id_map.keys.compact - - unless keys.empty? - table = klass.arel_table - method = in_or_equal(keys) - conditions = table[primary_key].send(*method) - - custom_conditions = append_conditions(reflection, preload_options) - conditions = custom_conditions.inject(conditions) do |ast, cond| - ast.and cond - end - - associated_records = klass.unscoped.where(conditions).apply_finder_options(options.slice(:include, :select, :joins, :order)).to_a - else - associated_records = [] - end - - set_association_single_records(_id_map, reflection.name, associated_records, primary_key) - end - end - - def find_associated_records(ids, reflection, preload_options) - options = reflection.options - table = reflection.klass.arel_table - - conditions = [] - - key = reflection.foreign_key - - if interface = reflection.options[:as] - key = "#{interface}_id" - conditions << table["#{interface}_type"].eq(base_class.sti_name) - end - - conditions.concat append_conditions(reflection, preload_options) - - find_options = { - :select => preload_options[:select] || options[:select] || table[Arel.star], - :include => preload_options[:include] || options[:include], - :joins => options[:joins], - :group => preload_options[:group] || options[:group], - :order => preload_options[:order] || options[:order] - } - - associated_records(ids) do |some_ids| - method = in_or_equal(some_ids) - where = table.create_and(conditions + [table[key].send(*method)]) - - reflection.klass.scoped.apply_finder_options(find_options.merge(:conditions => where)).to_a - end - end - - def process_conditions(conditions, klass = self) - if conditions.respond_to?(:to_proc) - conditions = instance_eval(&conditions) - end - - klass.send(:sanitize_sql, conditions) - end - - def append_conditions(reflection, preload_options) - [ - ('(' + process_conditions(reflection.options[:conditions], reflection.klass) + ')' if reflection.options[:conditions]), - ('(' + process_conditions(preload_options[:conditions]) + ')' if preload_options[:conditions]), - ].compact.map { |x| Arel.sql x } - end - - def in_or_equal(ids) - ids.length == 1 ? ['eq', ids.first] : ['in', ids] - end - - # Some databases impose a limit on the number of ids in a list (in Oracle its 1000) - # Make several smaller queries if necessary or make one query if the adapter supports it - def associated_records(ids) - in_clause_length = connection.in_clause_length || ids.size - records = [] - ids.each_slice(in_clause_length) do |some_ids| - records.concat yield(some_ids) - end - records - end - end - end -end diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index e0b4db498d..e91cbd7f33 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -5,7 +5,6 @@ require 'active_support/core_ext/object/blank' require 'active_support/core_ext/string/conversions' require 'active_support/core_ext/module/remove_method' require 'active_support/core_ext/class/attribute' -require 'active_record/associations/class_methods/join_dependency' module ActiveRecord class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc: @@ -143,6 +142,9 @@ module ActiveRecord autoload :HasAndBelongsToMany, 'active_record/associations/builder/has_and_belongs_to_many' end + autoload :Preloader, 'active_record/associations/preloader' + autoload :JoinDependency, 'active_record/associations/join_dependency' + # Clears out the association cache. def clear_association_cache #:nodoc: @association_cache.clear if persisted? diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency.rb deleted file mode 100644 index b711ff35ca..0000000000 --- a/activerecord/lib/active_record/associations/class_methods/join_dependency.rb +++ /dev/null @@ -1,233 +0,0 @@ -require 'active_record/associations/class_methods/join_dependency/join_part' -require 'active_record/associations/class_methods/join_dependency/join_base' -require 'active_record/associations/class_methods/join_dependency/join_association' - -module ActiveRecord - module Associations - module ClassMethods - class JoinDependency # :nodoc: - attr_reader :join_parts, :reflections, :table_aliases, :active_record - - def initialize(base, associations, joins) - @active_record = base - @table_joins = joins - @join_parts = [JoinBase.new(base)] - @associations = {} - @reflections = [] - @table_aliases = Hash.new do |h,name| - h[name] = count_aliases_from_table_joins(name.downcase) - end - @table_aliases[base.table_name] = 1 - build(associations) - end - - def graft(*associations) - associations.each do |association| - join_associations.detect {|a| association == a} || - build(association.reflection.name, association.find_parent_in(self) || join_base, association.join_type) - end - self - end - - def join_associations - join_parts.last(join_parts.length - 1) - end - - def join_base - join_parts.first - end - - def columns - join_parts.collect { |join_part| - table = join_part.aliased_table - join_part.column_names_with_alias.collect{ |column_name, aliased_name| - table[column_name].as Arel.sql(aliased_name) - } - }.flatten - end - - def count_aliases_from_table_joins(name) - return 0 if Arel::Table === @table_joins - - # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase - quoted_name = active_record.connection.quote_table_name(name).downcase - - @table_joins.map { |join| - # Table names + table aliases - join.left.downcase.scan( - /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/ - ).size - }.sum - end - - def instantiate(rows) - primary_key = join_base.aliased_primary_key - parents = {} - - records = rows.map { |model| - primary_id = model[primary_key] - parent = parents[primary_id] ||= join_base.instantiate(model) - construct(parent, @associations, join_associations, model) - parent - }.uniq - - remove_duplicate_results!(active_record, records, @associations) - records - end - - def remove_duplicate_results!(base, records, associations) - case associations - when Symbol, String - reflection = base.reflections[associations] - remove_uniq_by_reflection(reflection, records) - when Array - associations.each do |association| - remove_duplicate_results!(base, records, association) - end - when Hash - associations.keys.each do |name| - reflection = base.reflections[name] - remove_uniq_by_reflection(reflection, records) - - parent_records = [] - records.each do |record| - if descendant = record.send(reflection.name) - if reflection.collection? - parent_records.concat descendant.target.uniq - else - parent_records << descendant - end - end - end - - remove_duplicate_results!(reflection.klass, parent_records, associations[name]) unless parent_records.empty? - end - end - end - - protected - - def cache_joined_association(association) - associations = [] - parent = association.parent - while parent != join_base - associations.unshift(parent.reflection.name) - parent = parent.parent - end - ref = @associations - associations.each do |key| - ref = ref[key] - end - ref[association.reflection.name] ||= {} - end - - def build(associations, parent = nil, join_type = Arel::InnerJoin) - parent ||= join_parts.last - case associations - when Symbol, String - reflection = parent.reflections[associations.to_s.intern] or - raise ConfigurationError, "Association named '#{ associations }' was not found; perhaps you misspelled it?" - unless join_association = find_join_association(reflection, parent) - @reflections << reflection - join_association = build_join_association(reflection, parent) - join_association.join_type = join_type - @join_parts << join_association - cache_joined_association(join_association) - end - join_association - when Array - associations.each do |association| - build(association, parent, join_type) - end - when Hash - associations.keys.sort_by { |a| a.to_s }.each do |name| - join_association = build(name, parent, join_type) - build(associations[name], join_association, join_type) - end - else - raise ConfigurationError, associations.inspect - end - end - - def find_join_association(name_or_reflection, parent) - if String === name_or_reflection - name_or_reflection = name_or_reflection.to_sym - end - - join_associations.detect { |j| - j.reflection == name_or_reflection && j.parent == parent - } - end - - def remove_uniq_by_reflection(reflection, records) - if reflection && reflection.collection? - records.each { |record| record.send(reflection.name).target.uniq! } - end - end - - def build_join_association(reflection, parent) - JoinAssociation.new(reflection, self, parent) - end - - def construct(parent, associations, join_parts, row) - case associations - when Symbol, String - name = associations.to_s - - join_part = join_parts.detect { |j| - j.reflection.name.to_s == name && - j.parent_table_name == parent.class.table_name } - - raise(ConfigurationError, "No such association") unless join_part - - join_parts.delete(join_part) - construct_association(parent, join_part, row) - when Array - associations.each do |association| - construct(parent, association, join_parts, row) - end - when Hash - associations.sort_by { |k,_| k.to_s }.each do |association_name, assoc| - association = construct(parent, association_name, join_parts, row) - construct(association, assoc, join_parts, row) if association - end - else - raise ConfigurationError, associations.inspect - end - end - - def construct_association(record, join_part, row) - return if record.id.to_s != join_part.parent.record_id(row).to_s - - macro = join_part.reflection.macro - if macro == :has_one - return if record.association_cache.key?(join_part.reflection.name) - association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil? - set_target_and_inverse(join_part, association, record) - else - return if row[join_part.aliased_primary_key].nil? - association = join_part.instantiate(row) - case macro - when :has_many, :has_and_belongs_to_many - other = record.association(join_part.reflection.name) - other.loaded! - other.target.push(association) - other.set_inverse_instance(association) - when :belongs_to - set_target_and_inverse(join_part, association, record) - else - raise ConfigurationError, "unknown macro: #{join_part.reflection.macro}" - end - end - association - end - - def set_target_and_inverse(join_part, association, record) - other = record.association(join_part.reflection.name) - other.target = association - other.set_inverse_instance(association) - end - end - end - end -end diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb deleted file mode 100644 index aaa475109e..0000000000 --- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_association.rb +++ /dev/null @@ -1,281 +0,0 @@ -module ActiveRecord - module Associations - module ClassMethods - class JoinDependency # :nodoc: - class JoinAssociation < JoinPart # :nodoc: - # The reflection of the association represented - attr_reader :reflection - - # The JoinDependency object which this JoinAssociation exists within. This is mainly - # relevant for generating aliases which do not conflict with other joins which are - # part of the query. - attr_reader :join_dependency - - # A JoinBase instance representing the active record we are joining onto. - # (So in Author.has_many :posts, the Author would be that base record.) - attr_reader :parent - - # What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin - attr_accessor :join_type - - # These implement abstract methods from the superclass - attr_reader :aliased_prefix, :aliased_table_name - - delegate :options, :through_reflection, :source_reflection, :to => :reflection - delegate :table, :table_name, :to => :parent, :prefix => :parent - - def initialize(reflection, join_dependency, parent = nil) - reflection.check_validity! - - if reflection.options[:polymorphic] - raise EagerLoadPolymorphicError.new(reflection) - end - - super(reflection.klass) - - @reflection = reflection - @join_dependency = join_dependency - @parent = parent - @join_type = Arel::InnerJoin - @aliased_prefix = "t#{ join_dependency.join_parts.size }" - - # This must be done eagerly upon initialisation because the alias which is produced - # depends on the state of the join dependency, but we want it to work the same way - # every time. - allocate_aliases - @table = Arel::Table.new( - table_name, :as => aliased_table_name, :engine => arel_engine - ) - end - - def ==(other) - other.class == self.class && - other.reflection == reflection && - other.parent == parent - end - - def find_parent_in(other_join_dependency) - other_join_dependency.join_parts.detect do |join_part| - parent == join_part - end - end - - def join_to(relation) - send("join_#{reflection.macro}_to", relation) - end - - def join_relation(joining_relation) - self.join_type = Arel::OuterJoin - joining_relation.joins(self) - end - - attr_reader :table - # More semantic name given we are talking about associations - alias_method :target_table, :table - - protected - - def aliased_table_name_for(name, suffix = nil) - aliases = @join_dependency.table_aliases - - if aliases[name] != 0 # We need an alias - connection = active_record.connection - - name = connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}" - aliases[name] += 1 - name = name[0, connection.table_alias_length-3] + "_#{aliases[name]}" if aliases[name] > 1 - else - aliases[name] += 1 - end - - name - end - - def pluralize(table_name) - ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name - end - - private - - def allocate_aliases - @aliased_table_name = aliased_table_name_for(table_name) - - if reflection.macro == :has_and_belongs_to_many - @aliased_join_table_name = aliased_table_name_for(reflection.options[:join_table], "_join") - elsif [:has_many, :has_one].include?(reflection.macro) && reflection.options[:through] - @aliased_join_table_name = aliased_table_name_for(reflection.through_reflection.klass.table_name, "_join") - end - end - - def process_conditions(conditions, table_name) - if conditions.respond_to?(:to_proc) - conditions = instance_eval(&conditions) - end - - Arel.sql(sanitize_sql(conditions, table_name)) - end - - def sanitize_sql(condition, table_name) - active_record.send(:sanitize_sql, condition, table_name) - end - - def join_target_table(relation, condition) - conditions = [condition] - - # If the target table is an STI model then we must be sure to only include records of - # its type and its sub-types. - unless active_record.descends_from_active_record? - sti_column = target_table[active_record.inheritance_column] - subclasses = active_record.descendants - sti_condition = sti_column.eq(active_record.sti_name) - - conditions << subclasses.inject(sti_condition) { |attr,subclass| - attr.or(sti_column.eq(subclass.sti_name)) - } - end - - # If the reflection has conditions, add them - if options[:conditions] - conditions << process_conditions(options[:conditions], aliased_table_name) - end - - ands = relation.create_and(conditions) - - join = relation.create_join( - target_table, - relation.create_on(ands), - join_type) - - relation.from join - end - - def join_has_and_belongs_to_many_to(relation) - join_table = Arel::Table.new( - options[:join_table] - ).alias(@aliased_join_table_name) - - fk = options[:foreign_key] || reflection.active_record.to_s.foreign_key - klass_fk = options[:association_foreign_key] || reflection.klass.to_s.foreign_key - - relation = relation.join(join_table, join_type) - relation = relation.on( - join_table[fk]. - eq(parent_table[reflection.active_record.primary_key]) - ) - - join_target_table( - relation, - target_table[reflection.klass.primary_key]. - eq(join_table[klass_fk]) - ) - end - - def join_has_many_to(relation) - if reflection.options[:through] - join_has_many_through_to(relation) - elsif reflection.options[:as] - join_has_many_polymorphic_to(relation) - else - foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key - primary_key = options[:primary_key] || parent.primary_key - - join_target_table( - relation, - target_table[foreign_key]. - eq(parent_table[primary_key]) - ) - end - end - alias :join_has_one_to :join_has_many_to - - def join_has_many_through_to(relation) - join_table = Arel::Table.new( - through_reflection.klass.table_name - ).alias @aliased_join_table_name - - jt_conditions = [] - first_key = second_key = nil - - if through_reflection.macro == :belongs_to - jt_primary_key = through_reflection.foreign_key - jt_foreign_key = through_reflection.association_primary_key - else - jt_primary_key = through_reflection.active_record_primary_key - jt_foreign_key = through_reflection.foreign_key - - if through_reflection.options[:as] # has_many :through against a polymorphic join - jt_conditions << - join_table["#{through_reflection.options[:as]}_type"]. - eq(parent.active_record.base_class.name) - end - end - - case source_reflection.macro - when :has_many - second_key = options[:foreign_key] || primary_key - - if source_reflection.options[:as] - first_key = "#{source_reflection.options[:as]}_id" - else - first_key = through_reflection.klass.base_class.to_s.foreign_key - end - - unless through_reflection.klass.descends_from_active_record? - jt_conditions << - join_table[through_reflection.active_record.inheritance_column]. - eq(through_reflection.klass.sti_name) - end - when :belongs_to - first_key = primary_key - - if reflection.options[:source_type] - second_key = source_reflection.association_foreign_key - - jt_conditions << - join_table[reflection.source_reflection.foreign_type]. - eq(reflection.options[:source_type]) - else - second_key = source_reflection.foreign_key - end - end - - jt_conditions << - parent_table[jt_primary_key]. - eq(join_table[jt_foreign_key]) - - if through_reflection.options[:conditions] - jt_conditions << process_conditions(through_reflection.options[:conditions], aliased_table_name) - end - - relation = relation.join(join_table, join_type).on(*jt_conditions) - - join_target_table( - relation, - target_table[first_key].eq(join_table[second_key]) - ) - end - - def join_has_many_polymorphic_to(relation) - join_target_table( - relation, - target_table["#{reflection.options[:as]}_id"]. - eq(parent_table[parent.primary_key]).and( - target_table["#{reflection.options[:as]}_type"]. - eq(parent.active_record.base_class.name)) - ) - end - - def join_belongs_to_to(relation) - foreign_key = options[:foreign_key] || reflection.foreign_key - primary_key = options[:primary_key] || reflection.klass.primary_key - - join_target_table( - relation, - target_table[primary_key].eq(parent_table[foreign_key]) - ) - end - end - end - end - end -end diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb deleted file mode 100644 index 67567f06df..0000000000 --- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_base.rb +++ /dev/null @@ -1,26 +0,0 @@ -module ActiveRecord - module Associations - module ClassMethods - class JoinDependency # :nodoc: - class JoinBase < JoinPart # :nodoc: - def ==(other) - other.class == self.class && - other.active_record == active_record - end - - def aliased_prefix - "t0" - end - - def table - Arel::Table.new(table_name, arel_engine) - end - - def aliased_table_name - active_record.table_name - end - end - end - end - end -end diff --git a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb deleted file mode 100644 index cd16ae5a8b..0000000000 --- a/activerecord/lib/active_record/associations/class_methods/join_dependency/join_part.rb +++ /dev/null @@ -1,80 +0,0 @@ -module ActiveRecord - module Associations - module ClassMethods - class JoinDependency # :nodoc: - # A JoinPart represents a part of a JoinDependency. It is an abstract class, inherited - # by JoinBase and JoinAssociation. A JoinBase represents the Active Record which - # everything else is being joined onto. A JoinAssociation represents an association which - # is joining to the base. A JoinAssociation may result in more than one actual join - # operations (for example a has_and_belongs_to_many JoinAssociation would result in - # two; one for the join table and one for the target table). - class JoinPart # :nodoc: - # The Active Record class which this join part is associated 'about'; for a JoinBase - # this is the actual base model, for a JoinAssociation this is the target model of the - # association. - attr_reader :active_record - - delegate :table_name, :column_names, :primary_key, :reflections, :arel_engine, :to => :active_record - - def initialize(active_record) - @active_record = active_record - @cached_record = {} - @column_names_with_alias = nil - end - - def aliased_table - Arel::Nodes::TableAlias.new aliased_table_name, table - end - - def ==(other) - raise NotImplementedError - end - - # An Arel::Table for the active_record - def table - raise NotImplementedError - end - - # The prefix to be used when aliasing columns in the active_record's table - def aliased_prefix - raise NotImplementedError - end - - # The alias for the active_record's table - def aliased_table_name - raise NotImplementedError - end - - # The alias for the primary key of the active_record's table - def aliased_primary_key - "#{aliased_prefix}_r0" - end - - # An array of [column_name, alias] pairs for the table - def column_names_with_alias - unless @column_names_with_alias - @column_names_with_alias = [] - - ([primary_key] + (column_names - [primary_key])).each_with_index do |column_name, i| - @column_names_with_alias << [column_name, "#{aliased_prefix}_r#{i}"] - end - end - @column_names_with_alias - end - - def extract_record(row) - Hash[column_names_with_alias.map{|cn, an| [cn, row[an]]}] - end - - def record_id(row) - row[aliased_primary_key] - end - - def instantiate(row) - @cached_record[record_id(row)] ||= active_record.send(:instantiate, extract_record(row)) - end - end - end - end - end -end diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb new file mode 100644 index 0000000000..c7c3cf521c --- /dev/null +++ b/activerecord/lib/active_record/associations/join_dependency.rb @@ -0,0 +1,231 @@ +module ActiveRecord + module Associations + class JoinDependency # :nodoc: + autoload :JoinPart, 'active_record/associations/join_dependency/join_part' + autoload :JoinBase, 'active_record/associations/join_dependency/join_base' + autoload :JoinAssociation, 'active_record/associations/join_dependency/join_association' + + attr_reader :join_parts, :reflections, :table_aliases, :active_record + + def initialize(base, associations, joins) + @active_record = base + @table_joins = joins + @join_parts = [JoinBase.new(base)] + @associations = {} + @reflections = [] + @table_aliases = Hash.new do |h,name| + h[name] = count_aliases_from_table_joins(name.downcase) + end + @table_aliases[base.table_name] = 1 + build(associations) + end + + def graft(*associations) + associations.each do |association| + join_associations.detect {|a| association == a} || + build(association.reflection.name, association.find_parent_in(self) || join_base, association.join_type) + end + self + end + + def join_associations + join_parts.last(join_parts.length - 1) + end + + def join_base + join_parts.first + end + + def columns + join_parts.collect { |join_part| + table = join_part.aliased_table + join_part.column_names_with_alias.collect{ |column_name, aliased_name| + table[column_name].as Arel.sql(aliased_name) + } + }.flatten + end + + def count_aliases_from_table_joins(name) + return 0 if Arel::Table === @table_joins + + # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase + quoted_name = active_record.connection.quote_table_name(name).downcase + + @table_joins.map { |join| + # Table names + table aliases + join.left.downcase.scan( + /join(?:\s+\w+)?\s+(\S+\s+)?#{quoted_name}\son/ + ).size + }.sum + end + + def instantiate(rows) + primary_key = join_base.aliased_primary_key + parents = {} + + records = rows.map { |model| + primary_id = model[primary_key] + parent = parents[primary_id] ||= join_base.instantiate(model) + construct(parent, @associations, join_associations, model) + parent + }.uniq + + remove_duplicate_results!(active_record, records, @associations) + records + end + + def remove_duplicate_results!(base, records, associations) + case associations + when Symbol, String + reflection = base.reflections[associations] + remove_uniq_by_reflection(reflection, records) + when Array + associations.each do |association| + remove_duplicate_results!(base, records, association) + end + when Hash + associations.keys.each do |name| + reflection = base.reflections[name] + remove_uniq_by_reflection(reflection, records) + + parent_records = [] + records.each do |record| + if descendant = record.send(reflection.name) + if reflection.collection? + parent_records.concat descendant.target.uniq + else + parent_records << descendant + end + end + end + + remove_duplicate_results!(reflection.klass, parent_records, associations[name]) unless parent_records.empty? + end + end + end + + protected + + def cache_joined_association(association) + associations = [] + parent = association.parent + while parent != join_base + associations.unshift(parent.reflection.name) + parent = parent.parent + end + ref = @associations + associations.each do |key| + ref = ref[key] + end + ref[association.reflection.name] ||= {} + end + + def build(associations, parent = nil, join_type = Arel::InnerJoin) + parent ||= join_parts.last + case associations + when Symbol, String + reflection = parent.reflections[associations.to_s.intern] or + raise ConfigurationError, "Association named '#{ associations }' was not found; perhaps you misspelled it?" + unless join_association = find_join_association(reflection, parent) + @reflections << reflection + join_association = build_join_association(reflection, parent) + join_association.join_type = join_type + @join_parts << join_association + cache_joined_association(join_association) + end + join_association + when Array + associations.each do |association| + build(association, parent, join_type) + end + when Hash + associations.keys.sort_by { |a| a.to_s }.each do |name| + join_association = build(name, parent, join_type) + build(associations[name], join_association, join_type) + end + else + raise ConfigurationError, associations.inspect + end + end + + def find_join_association(name_or_reflection, parent) + if String === name_or_reflection + name_or_reflection = name_or_reflection.to_sym + end + + join_associations.detect { |j| + j.reflection == name_or_reflection && j.parent == parent + } + end + + def remove_uniq_by_reflection(reflection, records) + if reflection && reflection.collection? + records.each { |record| record.send(reflection.name).target.uniq! } + end + end + + def build_join_association(reflection, parent) + JoinAssociation.new(reflection, self, parent) + end + + def construct(parent, associations, join_parts, row) + case associations + when Symbol, String + name = associations.to_s + + join_part = join_parts.detect { |j| + j.reflection.name.to_s == name && + j.parent_table_name == parent.class.table_name } + + raise(ConfigurationError, "No such association") unless join_part + + join_parts.delete(join_part) + construct_association(parent, join_part, row) + when Array + associations.each do |association| + construct(parent, association, join_parts, row) + end + when Hash + associations.sort_by { |k,_| k.to_s }.each do |association_name, assoc| + association = construct(parent, association_name, join_parts, row) + construct(association, assoc, join_parts, row) if association + end + else + raise ConfigurationError, associations.inspect + end + end + + def construct_association(record, join_part, row) + return if record.id.to_s != join_part.parent.record_id(row).to_s + + macro = join_part.reflection.macro + if macro == :has_one + return if record.association_cache.key?(join_part.reflection.name) + association = join_part.instantiate(row) unless row[join_part.aliased_primary_key].nil? + set_target_and_inverse(join_part, association, record) + else + return if row[join_part.aliased_primary_key].nil? + association = join_part.instantiate(row) + case macro + when :has_many, :has_and_belongs_to_many + other = record.association(join_part.reflection.name) + other.loaded! + other.target.push(association) + other.set_inverse_instance(association) + when :belongs_to + set_target_and_inverse(join_part, association, record) + else + raise ConfigurationError, "unknown macro: #{join_part.reflection.macro}" + end + end + association + end + + def set_target_and_inverse(join_part, association, record) + other = record.association(join_part.reflection.name) + other.target = association + other.set_inverse_instance(association) + end + end + end +end diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb new file mode 100644 index 0000000000..ebe39c35fe --- /dev/null +++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb @@ -0,0 +1,279 @@ +module ActiveRecord + module Associations + class JoinDependency # :nodoc: + class JoinAssociation < JoinPart # :nodoc: + # The reflection of the association represented + attr_reader :reflection + + # The JoinDependency object which this JoinAssociation exists within. This is mainly + # relevant for generating aliases which do not conflict with other joins which are + # part of the query. + attr_reader :join_dependency + + # A JoinBase instance representing the active record we are joining onto. + # (So in Author.has_many :posts, the Author would be that base record.) + attr_reader :parent + + # What type of join will be generated, either Arel::InnerJoin (default) or Arel::OuterJoin + attr_accessor :join_type + + # These implement abstract methods from the superclass + attr_reader :aliased_prefix, :aliased_table_name + + delegate :options, :through_reflection, :source_reflection, :to => :reflection + delegate :table, :table_name, :to => :parent, :prefix => :parent + + def initialize(reflection, join_dependency, parent = nil) + reflection.check_validity! + + if reflection.options[:polymorphic] + raise EagerLoadPolymorphicError.new(reflection) + end + + super(reflection.klass) + + @reflection = reflection + @join_dependency = join_dependency + @parent = parent + @join_type = Arel::InnerJoin + @aliased_prefix = "t#{ join_dependency.join_parts.size }" + + # This must be done eagerly upon initialisation because the alias which is produced + # depends on the state of the join dependency, but we want it to work the same way + # every time. + allocate_aliases + @table = Arel::Table.new( + table_name, :as => aliased_table_name, :engine => arel_engine + ) + end + + def ==(other) + other.class == self.class && + other.reflection == reflection && + other.parent == parent + end + + def find_parent_in(other_join_dependency) + other_join_dependency.join_parts.detect do |join_part| + parent == join_part + end + end + + def join_to(relation) + send("join_#{reflection.macro}_to", relation) + end + + def join_relation(joining_relation) + self.join_type = Arel::OuterJoin + joining_relation.joins(self) + end + + attr_reader :table + # More semantic name given we are talking about associations + alias_method :target_table, :table + + protected + + def aliased_table_name_for(name, suffix = nil) + aliases = @join_dependency.table_aliases + + if aliases[name] != 0 # We need an alias + connection = active_record.connection + + name = connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}" + aliases[name] += 1 + name = name[0, connection.table_alias_length-3] + "_#{aliases[name]}" if aliases[name] > 1 + else + aliases[name] += 1 + end + + name + end + + def pluralize(table_name) + ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name + end + + private + + def allocate_aliases + @aliased_table_name = aliased_table_name_for(table_name) + + if reflection.macro == :has_and_belongs_to_many + @aliased_join_table_name = aliased_table_name_for(reflection.options[:join_table], "_join") + elsif [:has_many, :has_one].include?(reflection.macro) && reflection.options[:through] + @aliased_join_table_name = aliased_table_name_for(reflection.through_reflection.klass.table_name, "_join") + end + end + + def process_conditions(conditions, table_name) + if conditions.respond_to?(:to_proc) + conditions = instance_eval(&conditions) + end + + Arel.sql(sanitize_sql(conditions, table_name)) + end + + def sanitize_sql(condition, table_name) + active_record.send(:sanitize_sql, condition, table_name) + end + + def join_target_table(relation, condition) + conditions = [condition] + + # If the target table is an STI model then we must be sure to only include records of + # its type and its sub-types. + unless active_record.descends_from_active_record? + sti_column = target_table[active_record.inheritance_column] + subclasses = active_record.descendants + sti_condition = sti_column.eq(active_record.sti_name) + + conditions << subclasses.inject(sti_condition) { |attr,subclass| + attr.or(sti_column.eq(subclass.sti_name)) + } + end + + # If the reflection has conditions, add them + if options[:conditions] + conditions << process_conditions(options[:conditions], aliased_table_name) + end + + ands = relation.create_and(conditions) + + join = relation.create_join( + target_table, + relation.create_on(ands), + join_type) + + relation.from join + end + + def join_has_and_belongs_to_many_to(relation) + join_table = Arel::Table.new( + options[:join_table] + ).alias(@aliased_join_table_name) + + fk = options[:foreign_key] || reflection.active_record.to_s.foreign_key + klass_fk = options[:association_foreign_key] || reflection.klass.to_s.foreign_key + + relation = relation.join(join_table, join_type) + relation = relation.on( + join_table[fk]. + eq(parent_table[reflection.active_record.primary_key]) + ) + + join_target_table( + relation, + target_table[reflection.klass.primary_key]. + eq(join_table[klass_fk]) + ) + end + + def join_has_many_to(relation) + if reflection.options[:through] + join_has_many_through_to(relation) + elsif reflection.options[:as] + join_has_many_polymorphic_to(relation) + else + foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key + primary_key = options[:primary_key] || parent.primary_key + + join_target_table( + relation, + target_table[foreign_key]. + eq(parent_table[primary_key]) + ) + end + end + alias :join_has_one_to :join_has_many_to + + def join_has_many_through_to(relation) + join_table = Arel::Table.new( + through_reflection.klass.table_name + ).alias @aliased_join_table_name + + jt_conditions = [] + first_key = second_key = nil + + if through_reflection.macro == :belongs_to + jt_primary_key = through_reflection.foreign_key + jt_foreign_key = through_reflection.association_primary_key + else + jt_primary_key = through_reflection.active_record_primary_key + jt_foreign_key = through_reflection.foreign_key + + if through_reflection.options[:as] # has_many :through against a polymorphic join + jt_conditions << + join_table["#{through_reflection.options[:as]}_type"]. + eq(parent.active_record.base_class.name) + end + end + + case source_reflection.macro + when :has_many + second_key = options[:foreign_key] || primary_key + + if source_reflection.options[:as] + first_key = "#{source_reflection.options[:as]}_id" + else + first_key = through_reflection.klass.base_class.to_s.foreign_key + end + + unless through_reflection.klass.descends_from_active_record? + jt_conditions << + join_table[through_reflection.active_record.inheritance_column]. + eq(through_reflection.klass.sti_name) + end + when :belongs_to + first_key = primary_key + + if reflection.options[:source_type] + second_key = source_reflection.association_foreign_key + + jt_conditions << + join_table[reflection.source_reflection.foreign_type]. + eq(reflection.options[:source_type]) + else + second_key = source_reflection.foreign_key + end + end + + jt_conditions << + parent_table[jt_primary_key]. + eq(join_table[jt_foreign_key]) + + if through_reflection.options[:conditions] + jt_conditions << process_conditions(through_reflection.options[:conditions], aliased_table_name) + end + + relation = relation.join(join_table, join_type).on(*jt_conditions) + + join_target_table( + relation, + target_table[first_key].eq(join_table[second_key]) + ) + end + + def join_has_many_polymorphic_to(relation) + join_target_table( + relation, + target_table["#{reflection.options[:as]}_id"]. + eq(parent_table[parent.primary_key]).and( + target_table["#{reflection.options[:as]}_type"]. + eq(parent.active_record.base_class.name)) + ) + end + + def join_belongs_to_to(relation) + foreign_key = options[:foreign_key] || reflection.foreign_key + primary_key = options[:primary_key] || reflection.klass.primary_key + + join_target_table( + relation, + target_table[primary_key].eq(parent_table[foreign_key]) + ) + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/join_dependency/join_base.rb new file mode 100644 index 0000000000..3920e84976 --- /dev/null +++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb @@ -0,0 +1,24 @@ +module ActiveRecord + module Associations + class JoinDependency # :nodoc: + class JoinBase < JoinPart # :nodoc: + def ==(other) + other.class == self.class && + other.active_record == active_record + end + + def aliased_prefix + "t0" + end + + def table + Arel::Table.new(table_name, arel_engine) + end + + def aliased_table_name + active_record.table_name + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/join_dependency/join_part.rb b/activerecord/lib/active_record/associations/join_dependency/join_part.rb new file mode 100644 index 0000000000..3279e56e7d --- /dev/null +++ b/activerecord/lib/active_record/associations/join_dependency/join_part.rb @@ -0,0 +1,78 @@ +module ActiveRecord + module Associations + class JoinDependency # :nodoc: + # A JoinPart represents a part of a JoinDependency. It is an abstract class, inherited + # by JoinBase and JoinAssociation. A JoinBase represents the Active Record which + # everything else is being joined onto. A JoinAssociation represents an association which + # is joining to the base. A JoinAssociation may result in more than one actual join + # operations (for example a has_and_belongs_to_many JoinAssociation would result in + # two; one for the join table and one for the target table). + class JoinPart # :nodoc: + # The Active Record class which this join part is associated 'about'; for a JoinBase + # this is the actual base model, for a JoinAssociation this is the target model of the + # association. + attr_reader :active_record + + delegate :table_name, :column_names, :primary_key, :reflections, :arel_engine, :to => :active_record + + def initialize(active_record) + @active_record = active_record + @cached_record = {} + @column_names_with_alias = nil + end + + def aliased_table + Arel::Nodes::TableAlias.new aliased_table_name, table + end + + def ==(other) + raise NotImplementedError + end + + # An Arel::Table for the active_record + def table + raise NotImplementedError + end + + # The prefix to be used when aliasing columns in the active_record's table + def aliased_prefix + raise NotImplementedError + end + + # The alias for the active_record's table + def aliased_table_name + raise NotImplementedError + end + + # The alias for the primary key of the active_record's table + def aliased_primary_key + "#{aliased_prefix}_r0" + end + + # An array of [column_name, alias] pairs for the table + def column_names_with_alias + unless @column_names_with_alias + @column_names_with_alias = [] + + ([primary_key] + (column_names - [primary_key])).each_with_index do |column_name, i| + @column_names_with_alias << [column_name, "#{aliased_prefix}_r#{i}"] + end + end + @column_names_with_alias + end + + def extract_record(row) + Hash[column_names_with_alias.map{|cn, an| [cn, row[an]]}] + end + + def record_id(row) + row[aliased_primary_key] + end + + def instantiate(row) + @cached_record[record_id(row)] ||= active_record.send(:instantiate, extract_record(row)) + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb new file mode 100644 index 0000000000..fafed94ff2 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader.rb @@ -0,0 +1,177 @@ +module ActiveRecord + module Associations + # Implements the details of eager loading of Active Record associations. + # + # Note that 'eager loading' and 'preloading' are actually the same thing. + # However, there are two different eager loading strategies. + # + # The first one is by using table joins. This was only strategy available + # prior to Rails 2.1. Suppose that you have an Author model with columns + # 'name' and 'age', and a Book model with columns 'name' and 'sales'. Using + # this strategy, Active Record would try to retrieve all data for an author + # and all of its books via a single query: + # + # SELECT * FROM authors + # LEFT OUTER JOIN books ON authors.id = books.id + # WHERE authors.name = 'Ken Akamatsu' + # + # However, this could result in many rows that contain redundant data. After + # having received the first row, we already have enough data to instantiate + # the Author object. In all subsequent rows, only the data for the joined + # 'books' table is useful; the joined 'authors' data is just redundant, and + # processing this redundant data takes memory and CPU time. The problem + # quickly becomes worse and worse as the level of eager loading increases + # (i.e. if Active Record is to eager load the associations' associations as + # well). + # + # The second strategy is to use multiple database queries, one for each + # level of association. Since Rails 2.1, this is the default strategy. In + # situations where a table join is necessary (e.g. when the +:conditions+ + # option references an association's column), it will fallback to the table + # join strategy. + class Preloader #:nodoc: + autoload :Association, 'active_record/associations/preloader/association' + autoload :SingularAssociation, 'active_record/associations/preloader/singular_association' + autoload :CollectionAssociation, 'active_record/associations/preloader/collection_association' + autoload :ThroughAssociation, 'active_record/associations/preloader/through_association' + + autoload :HasMany, 'active_record/associations/preloader/has_many' + autoload :HasManyThrough, 'active_record/associations/preloader/has_many_through' + autoload :HasOne, 'active_record/associations/preloader/has_one' + autoload :HasOneThrough, 'active_record/associations/preloader/has_one_through' + autoload :HasAndBelongsToMany, 'active_record/associations/preloader/has_and_belongs_to_many' + autoload :BelongsTo, 'active_record/associations/preloader/belongs_to' + + attr_reader :records, :associations, :options, :model + + # Eager loads the named associations for the given Active Record record(s). + # + # In this description, 'association name' shall refer to the name passed + # to an association creation method. For example, a model that specifies + # <tt>belongs_to :author</tt>, <tt>has_many :buyers</tt> has association + # names +:author+ and +:buyers+. + # + # == Parameters + # +records+ is an array of ActiveRecord::Base. This array needs not be flat, + # i.e. +records+ itself may also contain arrays of records. In any case, + # +preload_associations+ will preload the all associations records by + # flattening +records+. + # + # +associations+ specifies one or more associations that you want to + # preload. It may be: + # - a Symbol or a String which specifies a single association name. For + # example, specifying +:books+ allows this method to preload all books + # for an Author. + # - an Array which specifies multiple association names. This array + # is processed recursively. For example, specifying <tt>[:avatar, :books]</tt> + # allows this method to preload an author's avatar as well as all of his + # books. + # - a Hash which specifies multiple association names, as well as + # association names for the to-be-preloaded association objects. For + # example, specifying <tt>{ :author => :avatar }</tt> will preload a + # book's author, as well as that author's avatar. + # + # +:associations+ has the same format as the +:include+ option for + # <tt>ActiveRecord::Base.find</tt>. So +associations+ could look like this: + # + # :books + # [ :books, :author ] + # { :author => :avatar } + # [ :books, { :author => :avatar } ] + # + # +options+ contains options that will be passed to ActiveRecord::Base#find + # (which is called under the hood for preloading records). But it is passed + # only one level deep in the +associations+ argument, i.e. it's not passed + # to the child associations when +associations+ is a Hash. + def initialize(records, associations, options = {}) + @records = Array.wrap(records).compact.uniq + @associations = Array.wrap(associations) + @options = options + end + + def run + unless records.empty? + associations.each { |association| preload(association) } + end + end + + private + + def preload(association) + case association + when Hash + preload_hash(association) + when String, Symbol + preload_one(association.to_sym) + else + raise ArgumentError, "#{association.inspect} was not recognised for preload" + end + end + + def preload_hash(association) + association.each do |parent, child| + Preloader.new(records, parent, options).run + Preloader.new(records.map { |record| record.send(parent) }.flatten, child).run + end + end + + # Not all records have the same class, so group then preload group on the reflection + # itself so that if various subclass share the same association then we do not split + # them unnecessarily + # + # Additionally, polymorphic belongs_to associations can have multiple associated + # classes, depending on the polymorphic_type field. So we group by the classes as + # well. + def preload_one(association) + grouped_records(association).each do |reflection, klasses| + klasses.each do |klass, records| + preloader_for(reflection).new(klass, records, reflection, options).run + end + end + end + + def grouped_records(association) + Hash[ + records_by_reflection(association).map do |reflection, records| + [reflection, records.group_by { |record| association_klass(reflection, record) }] + end + ] + end + + def records_by_reflection(association) + records.group_by do |record| + reflection = record.class.reflections[association] + + unless reflection + raise ActiveRecord::ConfigurationError, "Association named '#{association}' was not found; " \ + "perhaps you misspelled it?" + end + + reflection + end + end + + def association_klass(reflection, record) + if reflection.macro == :belongs_to && reflection.options[:polymorphic] + klass = record.send(reflection.foreign_type) + klass && klass.constantize + else + reflection.klass + end + end + + def preloader_for(reflection) + case reflection.macro + when :has_many + reflection.options[:through] ? HasManyThrough : HasMany + when :has_one + reflection.options[:through] ? HasOneThrough : HasOne + when :has_and_belongs_to_many + HasAndBelongsToMany + when :belongs_to + BelongsTo + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/association.rb b/activerecord/lib/active_record/associations/preloader/association.rb new file mode 100644 index 0000000000..7256dd5288 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/association.rb @@ -0,0 +1,126 @@ +module ActiveRecord + module Associations + class Preloader + class Association #:nodoc: + attr_reader :owners, :reflection, :preload_options, :model, :klass + + def initialize(klass, owners, reflection, preload_options) + @klass = klass + @owners = owners + @reflection = reflection + @preload_options = preload_options || {} + @model = owners.first && owners.first.class + @scoped = nil + @owners_by_key = nil + end + + def run + unless owners.first.association(reflection.name).loaded? + preload + end + end + + def preload + raise NotImplementedError + end + + def scoped + @scoped ||= build_scope + end + + def records_for(ids) + scoped.where(association_key.in(ids)) + end + + def table + klass.arel_table + end + + # The name of the key on the associated records + def association_key_name + raise NotImplementedError + end + + # This is overridden by HABTM as the condition should be on the foreign_key column in + # the join table + def association_key + table[association_key_name] + end + + # The name of the key on the model which declares the association + def owner_key_name + raise NotImplementedError + end + + # We're converting to a string here because postgres will return the aliased association + # key in a habtm as a string (for whatever reason) + def owners_by_key + @owners_by_key ||= owners.group_by do |owner| + key = owner[owner_key_name] + key && key.to_s + end + end + + def options + reflection.options + end + + private + + def associated_records_by_owner + owner_keys = owners.map { |owner| owner[owner_key_name] }.compact.uniq + + if klass.nil? || owner_keys.empty? + records = [] + else + # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000) + # Make several smaller queries if necessary or make one query if the adapter supports it + sliced = owner_keys.each_slice(model.connection.in_clause_length || owner_keys.size) + records = sliced.map { |slice| records_for(slice) }.flatten + end + + # Each record may have multiple owners, and vice-versa + records_by_owner = Hash[owners.map { |owner| [owner, []] }] + records.each do |record| + owner_key = record[association_key_name].to_s + + owners_by_key[owner_key].each do |owner| + records_by_owner[owner] << record + end + end + records_by_owner + end + + def build_scope + scope = klass.scoped + + scope = scope.where(process_conditions(options[:conditions])) + scope = scope.where(process_conditions(preload_options[:conditions])) + + scope = scope.select(preload_options[:select] || options[:select] || table[Arel.star]) + scope = scope.includes(preload_options[:include] || options[:include]) + + if options[:as] + scope = scope.where( + klass.table_name => { + reflection.type => model.base_class.sti_name + } + ) + end + + scope + end + + def process_conditions(conditions) + if conditions.respond_to?(:to_proc) + conditions = klass.send(:instance_eval, &conditions) + end + + if conditions + klass.send(:sanitize_sql, conditions) + end + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/belongs_to.rb b/activerecord/lib/active_record/associations/preloader/belongs_to.rb new file mode 100644 index 0000000000..5091d4717a --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/belongs_to.rb @@ -0,0 +1,17 @@ +module ActiveRecord + module Associations + class Preloader + class BelongsTo < SingularAssociation #:nodoc: + + def association_key_name + reflection.options[:primary_key] || klass && klass.primary_key + end + + def owner_key_name + reflection.foreign_key + end + + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/collection_association.rb b/activerecord/lib/active_record/associations/preloader/collection_association.rb new file mode 100644 index 0000000000..c248aeaaf6 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/collection_association.rb @@ -0,0 +1,24 @@ +module ActiveRecord + module Associations + class Preloader + class CollectionAssociation < Association #:nodoc: + + private + + def build_scope + super.order(preload_options[:order] || options[:order]) + end + + def preload + associated_records_by_owner.each do |owner, records| + association = owner.association(reflection.name) + association.loaded! + association.target.concat(records) + records.each { |record| association.set_inverse_instance(record) } + end + end + + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/preloader/has_and_belongs_to_many.rb new file mode 100644 index 0000000000..e794f05340 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/has_and_belongs_to_many.rb @@ -0,0 +1,58 @@ +module ActiveRecord + module Associations + class Preloader + class HasAndBelongsToMany < CollectionAssociation #:nodoc: + attr_reader :join_table + + def initialize(klass, records, reflection, preload_options) + super + @join_table = Arel::Table.new(options[:join_table]).alias('t0') + end + + # Unlike the other associations, we want to get a raw array of rows so that we can + # access the aliased column on the join table + def records_for(ids) + scope = super + klass.connection.select_all(scope.arel.to_sql, 'SQL', scope.bind_values) + end + + def owner_key_name + reflection.active_record_primary_key + end + + def association_key_name + 'ar_association_key_name' + end + + def association_key + join_table[reflection.foreign_key] + end + + private + + # Once we have used the join table column (in super), we manually instantiate the + # actual records + def associated_records_by_owner + super.each do |owner_key, rows| + rows.map! { |row| klass.instantiate(row) } + end + end + + def build_scope + super.joins(join).select(join_select) + end + + def join_select + association_key.as(Arel.sql(association_key_name)) + end + + def join + condition = table[reflection.association_primary_key].eq( + join_table[reflection.association_foreign_key]) + + table.create_join(join_table, table.create_on(condition)) + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/has_many.rb b/activerecord/lib/active_record/associations/preloader/has_many.rb new file mode 100644 index 0000000000..3ea91a8c11 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/has_many.rb @@ -0,0 +1,17 @@ +module ActiveRecord + module Associations + class Preloader + class HasMany < CollectionAssociation #:nodoc: + + def association_key_name + reflection.foreign_key + end + + def owner_key_name + reflection.active_record_primary_key + end + + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/has_many_through.rb b/activerecord/lib/active_record/associations/preloader/has_many_through.rb new file mode 100644 index 0000000000..c6e9ede356 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/has_many_through.rb @@ -0,0 +1,15 @@ +module ActiveRecord + module Associations + class Preloader + class HasManyThrough < CollectionAssociation #:nodoc: + include ThroughAssociation + + def associated_records_by_owner + super.each do |owner, records| + records.uniq! if options[:uniq] + end + end + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/has_one.rb b/activerecord/lib/active_record/associations/preloader/has_one.rb new file mode 100644 index 0000000000..848448bb48 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/has_one.rb @@ -0,0 +1,23 @@ +module ActiveRecord + module Associations + class Preloader + class HasOne < SingularAssociation #:nodoc: + + def association_key_name + reflection.foreign_key + end + + def owner_key_name + reflection.active_record_primary_key + end + + private + + def build_scope + super.order(preload_options[:order] || options[:order]) + end + + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/has_one_through.rb b/activerecord/lib/active_record/associations/preloader/has_one_through.rb new file mode 100644 index 0000000000..f063f85574 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/has_one_through.rb @@ -0,0 +1,9 @@ +module ActiveRecord + module Associations + class Preloader + class HasOneThrough < SingularAssociation #:nodoc: + include ThroughAssociation + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/singular_association.rb b/activerecord/lib/active_record/associations/preloader/singular_association.rb new file mode 100644 index 0000000000..44e804d785 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/singular_association.rb @@ -0,0 +1,21 @@ +module ActiveRecord + module Associations + class Preloader + class SingularAssociation < Association #:nodoc: + + private + + def preload + associated_records_by_owner.each do |owner, associated_records| + record = associated_records.first + + association = owner.association(reflection.name) + association.target = record + association.set_inverse_instance(record) + end + end + + end + end + end +end diff --git a/activerecord/lib/active_record/associations/preloader/through_association.rb b/activerecord/lib/active_record/associations/preloader/through_association.rb new file mode 100644 index 0000000000..d630fc4c63 --- /dev/null +++ b/activerecord/lib/active_record/associations/preloader/through_association.rb @@ -0,0 +1,66 @@ +module ActiveRecord + module Associations + class Preloader + module ThroughAssociation #:nodoc: + + def through_reflection + reflection.through_reflection + end + + def source_reflection + reflection.source_reflection + end + + def associated_records_by_owner + through_records = through_records_by_owner + + ActiveRecord::Associations::Preloader.new( + through_records.values.flatten, + source_reflection.name, options + ).run + + through_records.each do |owner, owner_through_records| + owner_through_records.map! { |r| r.send(source_reflection.name) }.flatten! + end + end + + private + + def through_records_by_owner + ActiveRecord::Associations::Preloader.new( + owners, through_reflection.name, + through_options + ).run + + Hash[owners.map do |owner| + through_records = Array.wrap(owner.send(through_reflection.name)) + + # Dont cache the association - we would only be caching a subset + if reflection.options[:source_type] && through_reflection.collection? + owner.association(through_reflection.name).reset + end + + [owner, through_records] + end] + end + + def through_options + through_options = {} + + if options[:source_type] + through_options[:conditions] = { reflection.foreign_type => options[:source_type] } + else + if options[:conditions] + through_options[:include] = options[:include] || options[:source] + through_options[:conditions] = options[:conditions] + end + + through_options[:order] = options[:order] + end + + through_options + end + end + end + end +end diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index 5c4998806b..b3204b2bda 100644 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -1950,7 +1950,7 @@ MSG include AttributeMethods::Dirty include ActiveModel::MassAssignmentSecurity include Callbacks, ActiveModel::Observing, Timestamp - include Associations, AssociationPreload, NamedScope + include Associations, NamedScope include IdentityMap include ActiveModel::SecurePassword diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb index 49659b3aa5..5de08953f9 100644 --- a/activerecord/lib/active_record/reflection.rb +++ b/activerecord/lib/active_record/reflection.rb @@ -210,6 +210,10 @@ module ActiveRecord @foreign_type ||= options[:foreign_type] || "#{name}_type" end + def type + @type ||= "#{options[:as]}_type" + end + def primary_key_column @primary_key_column ||= klass.columns.find { |c| c.name == klass.primary_key } end @@ -359,6 +363,8 @@ module ActiveRecord # Holds all the meta-data about a :through association as it was specified # in the Active Record class. class ThroughReflection < AssociationReflection #:nodoc: + delegate :association_primary_key, :foreign_type, :to => :source_reflection + # Gets the source of the through reflection. It checks both a singularized # and pluralized form for <tt>:belongs_to</tt> or <tt>:has_many</tt>. # @@ -402,10 +408,6 @@ module ActiveRecord through_reflection.options end - def association_primary_key - source_reflection.association_primary_key - end - def check_validity! if through_reflection.nil? raise HasManyThroughAssociationNotFoundError.new(active_record.name, self) diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb index b828cffa77..f939bedc81 100644 --- a/activerecord/lib/active_record/relation.rb +++ b/activerecord/lib/active_record/relation.rb @@ -86,7 +86,9 @@ module ActiveRecord preload = @preload_values preload += @includes_values unless eager_loading? - preload.each {|associations| @klass.send(:preload_associations, @records, associations) } + preload.each do |associations| + ActiveRecord::Associations::Preloader.new(@records, associations).run + end # @readonly_value is true only if set explicitly. @implicit_readonly is true if there # are JOINS and no explicit SELECT. diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb index 7f32e5538e..426000fde1 100644 --- a/activerecord/lib/active_record/relation/finder_methods.rb +++ b/activerecord/lib/active_record/relation/finder_methods.rb @@ -187,7 +187,7 @@ module ActiveRecord def find_with_associations including = (@eager_load_values + @includes_values).uniq - join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, []) + join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, []) relation = construct_relation_for_association_find(join_dependency) rows = connection.select_all(relation.to_sql, 'SQL', relation.bind_values) join_dependency.instantiate(rows) @@ -197,7 +197,7 @@ module ActiveRecord def construct_relation_for_association_calculations including = (@eager_load_values + @includes_values).uniq - join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, arel.froms.first) + join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, arel.froms.first) relation = except(:includes, :eager_load, :preload) apply_join_dependency(relation, join_dependency) end diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb index 4330d850fe..cd1d7108b3 100644 --- a/activerecord/lib/active_record/relation/query_methods.rb +++ b/activerecord/lib/active_record/relation/query_methods.rb @@ -236,7 +236,7 @@ module ActiveRecord 'string_join' when Hash, Symbol, Array 'association_join' - when ActiveRecord::Associations::ClassMethods::JoinDependency::JoinAssociation + when ActiveRecord::Associations::JoinDependency::JoinAssociation 'stashed_join' when Arel::Nodes::Join 'join_node' @@ -254,7 +254,7 @@ module ActiveRecord join_list = custom_join_ast(manager, string_joins) - join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new( + join_dependency = ActiveRecord::Associations::JoinDependency.new( @klass, association_joins, join_list diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb index ca71cd8ed3..26808ae931 100644 --- a/activerecord/test/cases/associations/eager_test.rb +++ b/activerecord/test/cases/associations/eager_test.rb @@ -120,30 +120,29 @@ class EagerAssociationTest < ActiveRecord::TestCase def test_load_associated_records_in_one_query_when_adapter_has_no_limit Post.connection.expects(:in_clause_length).at_least_once.returns(nil) - Post.expects(:i_was_called).with([1,2,3,4,5,6,7]).returns([1]) - associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids| - Post.i_was_called(some_ids) + + post = posts(:welcome) + assert_queries(2) do + Post.includes(:comments).where(:id => post.id).to_a end - assert_equal [1], associated_records end def test_load_associated_records_in_several_queries_when_many_ids_passed - Post.connection.expects(:in_clause_length).at_least_once.returns(5) - Post.expects(:i_was_called).with([1,2,3,4,5]).returns([1]) - Post.expects(:i_was_called).with([6,7]).returns([6]) - associated_records = Post.send(:associated_records, [1,2,3,4,5,6,7]) do |some_ids| - Post.i_was_called(some_ids) + Post.connection.expects(:in_clause_length).at_least_once.returns(1) + + post1, post2 = posts(:welcome), posts(:thinking) + assert_queries(3) do + Post.includes(:comments).where(:id => [post1.id, post2.id]).to_a end - assert_equal [1,6], associated_records end def test_load_associated_records_in_one_query_when_a_few_ids_passed - Post.connection.expects(:in_clause_length).at_least_once.returns(5) - Post.expects(:i_was_called).with([1,2,3]).returns([1]) - associated_records = Post.send(:associated_records, [1,2,3]) do |some_ids| - Post.i_was_called(some_ids) + Post.connection.expects(:in_clause_length).at_least_once.returns(3) + + post = posts(:welcome) + assert_queries(2) do + Post.includes(:comments).where(:id => post.id).to_a end - assert_equal [1], associated_records end def test_including_duplicate_objects_from_belongs_to diff --git a/activerecord/test/cases/associations/join_model_test.rb b/activerecord/test/cases/associations/join_model_test.rb index 6d7f905dc5..19303fef9f 100644 --- a/activerecord/test/cases/associations/join_model_test.rb +++ b/activerecord/test/cases/associations/join_model_test.rb @@ -214,7 +214,7 @@ class AssociationsJoinModelTest < ActiveRecord::TestCase end def test_has_many_with_piggyback - assert_equal "2", categories(:sti_test).authors.first.post_id.to_s + assert_equal "2", categories(:sti_test).authors_with_select.first.post_id.to_s end def test_include_has_many_through diff --git a/activerecord/test/cases/inheritance_test.rb b/activerecord/test/cases/inheritance_test.rb index 680d4ca5dd..b5d8314541 100644 --- a/activerecord/test/cases/inheritance_test.rb +++ b/activerecord/test/cases/inheritance_test.rb @@ -208,7 +208,7 @@ class InheritanceTest < ActiveRecord::TestCase def test_eager_load_belongs_to_primary_key_quoting con = Account.connection - assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} = 1/) do + assert_sql(/#{con.quote_table_name('companies')}.#{con.quote_column_name('id')} IN \(1\)/) do Account.find(1, :include => :firm) end end diff --git a/activerecord/test/models/category.rb b/activerecord/test/models/category.rb index 06908ea85e..8f37433ec6 100644 --- a/activerecord/test/models/category.rb +++ b/activerecord/test/models/category.rb @@ -22,7 +22,8 @@ class Category < ActiveRecord::Base end has_many :categorizations - has_many :authors, :through => :categorizations, :select => 'authors.*, categorizations.post_id' + has_many :authors, :through => :categorizations + has_many :authors_with_select, :through => :categorizations, :source => :author, :select => 'authors.*, categorizations.post_id' scope :general, :conditions => { :name => 'General' } end |