diff options
Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations.rb | 481 |
1 files changed, 248 insertions, 233 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index dc466eafc2..37dbff4061 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -39,14 +39,6 @@ module ActiveRecord end end - class HasManyThroughSourceAssociationMacroError < ActiveRecordError #:nodoc: - def initialize(reflection) - through_reflection = reflection.through_reflection - source_reflection = reflection.source_reflection - super("Invalid source reflection macro :#{source_reflection.macro}#{" :through" if source_reflection.options[:through]} for has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}. Use :source to specify the source reflection.") - end - end - class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ActiveRecordError #:nodoc: def initialize(owner, reflection) super("Cannot modify association '#{owner.class.name}##{reflection.name}' because the source reflection class '#{reflection.source_reflection.class_name}' is associated to '#{reflection.through_reflection.class_name}' via :#{reflection.source_reflection.macro}.") @@ -64,6 +56,12 @@ module ActiveRecord super("Cannot dissociate new records through '#{owner.class.name}##{reflection.name}' on '#{reflection.source_reflection.class_name rescue nil}##{reflection.source_reflection.name rescue nil}'. Both records must have an id in order to delete the has_many :through record associating them.") end end + + class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc + def initialize(owner, reflection) + super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.") + end + end class HasAndBelongsToManyAssociationWithPrimaryKeyError < ActiveRecordError #:nodoc: def initialize(reflection) @@ -113,6 +111,7 @@ module ActiveRecord autoload :HasManyThroughAssociation, 'active_record/associations/has_many_through_association' autoload :HasOneAssociation, 'active_record/associations/has_one_association' autoload :HasOneThroughAssociation, 'active_record/associations/has_one_through_association' + autoload :AliasTracker, 'active_record/associations/alias_tracker' # Clears out the association cache. def clear_association_cache #:nodoc: @@ -487,6 +486,49 @@ module ActiveRecord # @group.avatars << Avatar.new # this would work if User belonged_to Avatar rather than the other way around # @group.avatars.delete(@group.avatars.last) # so would this # + # === Nested Associations + # + # You can actually specify *any* association with the <tt>:through</tt> option, including an + # association which has a <tt>:through</tt> option itself. For example: + # + # class Author < ActiveRecord::Base + # has_many :posts + # has_many :comments, :through => :posts + # has_many :commenters, :through => :comments + # end + # + # class Post < ActiveRecord::Base + # has_many :comments + # end + # + # class Comment < ActiveRecord::Base + # belongs_to :commenter + # end + # + # @author = Author.first + # @author.commenters # => People who commented on posts written by the author + # + # An equivalent way of setting up this association this would be: + # + # class Author < ActiveRecord::Base + # has_many :posts + # has_many :commenters, :through => :posts + # end + # + # class Post < ActiveRecord::Base + # has_many :comments + # has_many :commenters, :through => :comments + # end + # + # class Comment < ActiveRecord::Base + # belongs_to :commenter + # end + # + # When using nested association, you will not be able to modify the association because there + # is not enough information to know what modification to make. For example, if you tried to + # add a <tt>Commenter</tt> in the example above, there would be no way to tell how to set up the + # intermediate <tt>Post</tt> and <tt>Comment</tt> objects. + # # === Polymorphic Associations # # Polymorphic associations on models are not restricted on what types of models they @@ -934,10 +976,11 @@ module ActiveRecord # [:as] # Specifies a polymorphic interface (See <tt>belongs_to</tt>). # [:through] - # Specifies a join model through which to perform the query. Options for <tt>:class_name</tt> - # and <tt>:foreign_key</tt> are ignored, as the association uses the source reflection. You - # can only use a <tt>:through</tt> query through a <tt>belongs_to</tt>, <tt>has_one</tt> - # or <tt>has_many</tt> association on the join model. The collection of join models + # Specifies a join model through which to perform the query. Options for <tt>:class_name</tt>, + # <tt>:primary_key</tt> and <tt>:foreign_key</tt> are ignored, as the association uses the + # source reflection. You can use a <tt>:through</tt> association through any other, + # association, but if other <tt>:through</tt> associations are involved then the resulting + # association will be read-only. Otherwise, the collection of join models # can be managed via the collection API. For example, new join models are created for # newly associated objects, and if some are gone their rows are deleted (directly, # no destroy callbacks are triggered). @@ -1061,10 +1104,10 @@ module ActiveRecord # you want to do a join but not include the joined columns. Do not forget to include the # primary and foreign keys, otherwise it will raise an error. # [:through] - # Specifies a Join Model through which to perform the query. Options for <tt>:class_name</tt> - # and <tt>:foreign_key</tt> are ignored, as the association uses the source reflection. You - # can only use a <tt>:through</tt> query through a <tt>has_one</tt> or <tt>belongs_to</tt> - # association on the join model. + # Specifies a Join Model through which to perform the query. Options for <tt>:class_name</tt>, + # <tt>:primary_key</tt>, and <tt>:foreign_key</tt> are ignored, as the association uses the + # source reflection. You can only use a <tt>:through</tt> query through a <tt>has_one</tt> + # or <tt>belongs_to</tt> association on the join model. # [:source] # Specifies the source association name used by <tt>has_one :through</tt> queries. # Only use it if the name cannot be inferred from the association. @@ -1833,7 +1876,7 @@ module ActiveRecord end class JoinDependency # :nodoc: - attr_reader :join_parts, :reflections, :table_aliases + attr_reader :join_parts, :reflections, :alias_tracker def initialize(base, associations, joins) @join_parts = [JoinBase.new(base, joins)] @@ -1841,8 +1884,8 @@ module ActiveRecord @reflections = [] @base_records_hash = {} @base_records_in_order = [] - @table_aliases = Hash.new(0) - @table_aliases[base.table_name] = 1 + @alias_tracker = AliasTracker.new(joins) + @alias_tracker.aliased_name_for(base.table_name) # Updates the count for base.table_name to 1 build(associations) end @@ -1862,17 +1905,6 @@ module ActiveRecord join_parts.first end - def count_aliases_from_table_joins(name) - # quoted_name should be downcased as some database adapters (Oracle) return quoted name in uppercase - quoted_name = join_base.active_record.connection.quote_table_name(name.downcase).downcase - join_sql = join_base.table_joins.to_s.downcase - join_sql.blank? ? 0 : - # Table names - join_sql.scan(/join(?:\s+\w+)?\s+#{quoted_name}\son/).size + - # Table aliases - join_sql.scan(/join(?:\s+\w+)?\s+\S+\s+#{quoted_name}\son/).size - end - def instantiate(rows) rows.each_with_index do |row, i| primary_id = join_base.record_id(row) @@ -2151,12 +2183,12 @@ module ActiveRecord # 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 + + attr_reader :aliased_prefix + + delegate :options, :through_reflection, :source_reflection, :through_reflection_chain, :to => :reflection delegate :table, :table_name, :to => :parent, :prefix => true + delegate :alias_tracker, :to => :join_dependency def initialize(reflection, join_dependency, parent = nil) reflection.check_validity! @@ -2166,16 +2198,14 @@ module ActiveRecord end super(reflection.klass) - - @reflection = reflection - @join_dependency = join_dependency - @parent = parent - @join_type = Arel::InnerJoin - - # 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 + + @reflection = reflection + @join_dependency = join_dependency + @parent = parent + @join_type = Arel::InnerJoin + @aliased_prefix = "t#{ join_dependency.join_parts.size }" + + setup_tables end def ==(other) @@ -2191,7 +2221,88 @@ module ActiveRecord end def join_to(relation) - send("join_#{reflection.macro}_to", relation) + # The chain starts with the target table, but we want to end with it here (makes + # more sense in this context) + chain = through_reflection_chain.reverse + + foreign_table = parent_table + index = 0 + + chain.each do |reflection| + table = @tables[index] + conditions = [] + + if reflection.source_reflection.nil? + case reflection.macro + when :belongs_to + key = reflection.association_primary_key + foreign_key = reflection.primary_key_name + when :has_many, :has_one + key = reflection.primary_key_name + foreign_key = reflection.active_record_primary_key + + conditions << polymorphic_conditions(reflection, table) + when :has_and_belongs_to_many + # For habtm, we need to deal with the join table at the same time as the + # target table (because unlike a :through association, there is no reflection + # to represent the join table) + table, join_table = table + + join_key = reflection.primary_key_name + join_foreign_key = reflection.active_record.primary_key + + relation = relation.join(join_table, join_type).on( + join_table[join_key]. + eq(foreign_table[join_foreign_key]) + ) + + # We've done the first join now, so update the foreign_table for the second + foreign_table = join_table + + key = reflection.klass.primary_key + foreign_key = reflection.association_foreign_key + end + else + case reflection.source_reflection.macro + when :belongs_to + key = reflection.association_primary_key + foreign_key = reflection.primary_key_name + + conditions << source_type_conditions(reflection, foreign_table) + when :has_many, :has_one + key = reflection.primary_key_name + foreign_key = reflection.source_reflection.active_record_primary_key + when :has_and_belongs_to_many + table, join_table = table + + join_key = reflection.primary_key_name + join_foreign_key = reflection.klass.primary_key + + relation = relation.join(join_table, join_type).on( + join_table[join_key]. + eq(foreign_table[join_foreign_key]) + ) + + foreign_table = join_table + + key = reflection.klass.primary_key + foreign_key = reflection.association_foreign_key + end + end + + conditions << table[key].eq(foreign_table[foreign_key]) + + conditions << reflection_conditions(index, table) + conditions << sti_conditions(reflection, table) + + relation = relation.join(table, join_type).on(*conditions.flatten.compact) + + # The current table in this iteration becomes the foreign table in the next + foreign_table = table + index += 1 + end + + relation end def join_relation(joining_relation) @@ -2200,213 +2311,117 @@ module ActiveRecord end def table - @table ||= Arel::Table.new( - table_name, :as => aliased_table_name, - :engine => arel_engine, :columns => active_record.columns - ) + if @tables.last.is_a?(Array) + @tables.last.first + else + @tables.last + end end - - # More semantic name given we are talking about associations - alias_method :target_table, :table - + + def aliased_table_name + table.table_alias || table.name + end + protected - def aliased_table_name_for(name, suffix = nil) - if @join_dependency.table_aliases[name].zero? - @join_dependency.table_aliases[name] = @join_dependency.count_aliases_from_table_joins(name) - end - - if !@join_dependency.table_aliases[name].zero? # We need an alias - name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}" - @join_dependency.table_aliases[name] += 1 - if @join_dependency.table_aliases[name] == 1 # First time we've seen this name - # Also need to count the aliases from the table_aliases to avoid incorrect count - @join_dependency.table_aliases[name] += @join_dependency.count_aliases_from_table_joins(name) - end - table_index = @join_dependency.table_aliases[name] - name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index}" if table_index > 1 - else - @join_dependency.table_aliases[name] += 1 - end - + def table_alias_for(reflection, join = false) + name = alias_tracker.pluralize(reflection.name) + name << "_#{parent_table_name}" + name << "_join" if join name end - def pluralize(table_name) - ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name - end - def interpolate_sql(sql) instance_eval("%@#{sql.gsub('@', '\@')}@", __FILE__, __LINE__) end private - - def allocate_aliases - @aliased_prefix = "t#{ join_dependency.join_parts.size }" - @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) - Arel.sql(interpolate_sql(sanitize_sql(conditions, table_name))) - end - - def join_target_table(relation, *conditions) - relation = relation.join(target_table, join_type) - - # 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] - - sti_condition = sti_column.eq(active_record.sti_name) - active_record.descendants.each do |subclass| - sti_condition = sti_condition.or(sti_column.eq(subclass.sti_name)) + + # Generate aliases and Arel::Table instances for each of the tables which we will + # later generate joins for. We must do this in advance in order to correctly allocate + # the proper alias. + def setup_tables + @tables = through_reflection_chain.map do |reflection| + aliased_table_name = alias_tracker.aliased_name_for( + reflection.table_name, + table_alias_for(reflection, reflection != self.reflection) + ) + + table = Arel::Table.new( + reflection.table_name, :engine => arel_engine, + :as => aliased_table_name, :columns => reflection.klass.columns + ) + + # For habtm, we have two Arel::Table instances related to a single reflection, so + # we just store them as a pair in the array. + if reflection.macro == :has_and_belongs_to_many || + (reflection.source_reflection && + reflection.source_reflection.macro == :has_and_belongs_to_many) + + join_table_name = (reflection.source_reflection || reflection).options[:join_table] + + aliased_join_table_name = alias_tracker.aliased_name_for( + join_table_name, + table_alias_for(reflection, true) + ) + + join_table = Arel::Table.new( + join_table_name, :engine => arel_engine, + :as => aliased_join_table_name + ) + + [table, join_table] + else + table end - - conditions << sti_condition end - - # If the reflection has conditions, add them - if options[:conditions] - conditions << process_conditions(options[:conditions], aliased_table_name) - end - - relation = relation.on(*conditions) - end - - def join_has_and_belongs_to_many_to(relation) - join_table = Arel::Table.new( - options[:join_table], :engine => arel_engine, - :as => @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]) - ) + + # The joins are generated from the through_reflection_chain in reverse order, so + # reverse the tables too (but it's important to generate the aliases in the 'forward' + # order, which is why we only do the reversal now. + @tables.reverse! + + @tables 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]) - ) + + def reflection_conditions(index, table) + @reflection.through_conditions.reverse[index].map do |condition| + Arel.sql(interpolate_sql(sanitize_sql( + condition, + table.table_alias || table.name + ))) 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, :engine => arel_engine, - :as => @aliased_join_table_name - ) - - jt_conditions = [] - jt_foreign_key = first_key = second_key = nil - - if through_reflection.options[:as] # has_many :through against a polymorphic join - as_key = through_reflection.options[:as].to_s - jt_foreign_key = as_key + '_id' - - jt_conditions << - join_table[as_key + '_type']. - eq(parent.active_record.base_class.name) - else - jt_foreign_key = through_reflection.primary_key_name - 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.options[:foreign_type]]. - eq(reflection.options[:source_type]) - else - second_key = source_reflection.primary_key_name + + def sti_conditions(reflection, table) + unless reflection.klass.descends_from_active_record? + sti_column = table[reflection.klass.inheritance_column] + + condition = sti_column.eq(reflection.klass.sti_name) + + reflection.klass.descendants.each do |subclass| + condition = condition.or(sti_column.eq(subclass.sti_name)) end + + condition end - - jt_conditions << - parent_table[parent.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]), - 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.primary_key_name - primary_key = options[:primary_key] || reflection.klass.primary_key - - join_target_table( - relation, - target_table[primary_key].eq(parent_table[foreign_key]) - ) - end - end + + def source_type_conditions(reflection, foreign_table) + if reflection.options[:source_type] + foreign_table[reflection.source_reflection.options[:foreign_type]]. + eq(reflection.options[:source_type]) + end + end + + def polymorphic_conditions(reflection, table) + if reflection.options[:as] + table["#{reflection.options[:as]}_type"]. + eq(reflection.active_record.base_class.name) + end + end end + end end end end |