diff options
Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
-rw-r--r-- | activerecord/lib/active_record/associations.rb | 35 |
1 files changed, 21 insertions, 14 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 1ca648d48d..a830b0e0e4 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -61,12 +61,18 @@ module ActiveRecord end end - class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ActiveRecordError #:nodoc: + class ThroughCantAssociateThroughHasOneOrManyReflection < 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}.") end end + class HasManyThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection #:nodoc: + end + + class HasOneThroughCantAssociateThroughHasOneOrManyReflection < ThroughCantAssociateThroughHasOneOrManyReflection #:nodoc: + end + class HasManyThroughCantAssociateNewRecords < ActiveRecordError #:nodoc: def initialize(owner, reflection) super("Cannot associate 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 create the has_many :through record associating them.") @@ -79,12 +85,18 @@ module ActiveRecord end end - class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc: + class ThroughNestedAssociationsAreReadonly < 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 HasManyThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly #:nodoc: + end + + class HasOneThroughNestedAssociationsAreReadonly < ThroughNestedAssociationsAreReadonly #:nodoc: + end + class EagerLoadPolymorphicError < ActiveRecordError #:nodoc: def initialize(reflection) super("Cannot eagerly load the polymorphic association #{reflection.name.inspect}") @@ -955,20 +967,16 @@ module ActiveRecord # The +traps+ association on +Dungeon+ and the +dungeon+ association on +Trap+ are # the inverse of each other and the inverse of the +dungeon+ association on +EvilWizard+ # is the +evil_wizard+ association on +Dungeon+ (and vice-versa). By default, - # Active Record doesn't know anything about these inverse relationships and so no object - # loading optimization is possible. For example: + # Active Record can guess the inverse of the association based on the name + # of the class. The result is the following: # # d = Dungeon.first # t = d.traps.first - # d.level == t.dungeon.level # => true - # d.level = 10 - # d.level == t.dungeon.level # => false + # d.object_id == t.dungeon.object_id # => true # # The +Dungeon+ instances +d+ and <tt>t.dungeon</tt> in the above example refer to - # the same object data from the database, but are actually different in-memory copies - # of that data. Specifying the <tt>:inverse_of</tt> option on associations lets you tell - # Active Record about inverse relationships and it will optimise object loading. For - # example, if we changed our model definitions to: + # the same in-memory instance since the association matches the name of the class. + # The result would be the same if we added +:inverse_of+ to our model definitions: # # class Dungeon < ActiveRecord::Base # has_many :traps, inverse_of: :dungeon @@ -983,15 +991,14 @@ module ActiveRecord # belongs_to :dungeon, inverse_of: :evil_wizard # end # - # Then, from our code snippet above, +d+ and <tt>t.dungeon</tt> are actually the same - # in-memory instance and our final <tt>d.level == t.dungeon.level</tt> will return +true+. - # # There are limitations to <tt>:inverse_of</tt> support: # # * does not work with <tt>:through</tt> associations. # * does not work with <tt>:polymorphic</tt> associations. # * for +belongs_to+ associations +has_many+ inverse associations are ignored. # + # For more information, see the documentation for the +:inverse_of+ option. + # # == Deleting from associations # # === Dependent associations |