diff options
Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations.rb | 231 |
1 files changed, 184 insertions, 47 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 714f623af3..35bc09bb10 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -4,6 +4,12 @@ require 'active_support/core_ext/module/remove_method' require 'active_record/errors' module ActiveRecord + class AssociationNotFoundError < ConfigurationError #:nodoc: + def initialize(record, association_name) + super("Association named '#{association_name}' was not found on #{record.class.name}; perhaps you misspelled it?") + end + end + class InverseOfAssociationNotFoundError < ActiveRecordError #:nodoc: def initialize(reflection, associated_class = nil) super("Could not find the inverse association for #{reflection.name} (#{reflection.options[:inverse_of].inspect} in #{associated_class.nil? ? reflection.class_name : associated_class.name})") @@ -40,12 +46,18 @@ module ActiveRecord end end + class HasOneAssociationPolymorphicThroughError < ActiveRecordError #:nodoc: + def initialize(owner_class_name, reflection) + super("Cannot have a has_one :through association '#{owner_class_name}##{reflection.name}' which goes through the polymorphic association '#{owner_class_name}##{reflection.through_reflection.name}'.") + end + end + class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError #:nodoc: def initialize(reflection) through_reflection = reflection.through_reflection source_reflection_names = reflection.source_reflection_names - source_associations = reflection.through_reflection.klass.reflect_on_all_associations.collect { |a| a.name.inspect } - super("Could not find the source association(s) #{source_reflection_names.collect{ |a| a.inspect }.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)}?") + source_associations = reflection.through_reflection.klass._reflections.keys + super("Could not find the source association(s) #{source_reflection_names.collect(&:inspect).to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)} in model #{through_reflection.klass}. Try 'has_many #{reflection.name.inspect}, :through => #{through_reflection.name.inspect}, :source => <name>'. Is it one of #{source_associations.to_sentence(:two_words_connector => ' or ', :last_word_connector => ', or ', :locale => :en)}?") end end @@ -104,6 +116,7 @@ module ActiveRecord autoload :Association, 'active_record/associations/association' autoload :SingularAssociation, 'active_record/associations/singular_association' autoload :CollectionAssociation, 'active_record/associations/collection_association' + autoload :ForeignAssociation, 'active_record/associations/foreign_association' autoload :CollectionProxy, 'active_record/associations/collection_proxy' autoload :BelongsToAssociation, 'active_record/associations/belongs_to_association' @@ -130,7 +143,6 @@ module ActiveRecord autoload :JoinDependency, 'active_record/associations/join_dependency' autoload :AssociationScope, 'active_record/associations/association_scope' autoload :AliasTracker, 'active_record/associations/alias_tracker' - autoload :JoinHelper, 'active_record/associations/join_helper' end # Clears out the association cache. @@ -146,7 +158,7 @@ module ActiveRecord association = association_instance_get(name) if association.nil? - reflection = self.class.reflect_on_association(name) + raise AssociationNotFoundError.new(self, name) unless reflection = self.class._reflect_on_association(name) association = reflection.association_class.new(self, reflection) association_instance_set(name, association) end @@ -197,12 +209,13 @@ module ActiveRecord # For instance, +attributes+ and +connection+ would be bad choices for association names. # # == Auto-generated methods + # See also Instance Public methods below for more details. # # === Singular associations (one-to-one) # | | belongs_to | # generated methods | belongs_to | :polymorphic | has_one # ----------------------------------+------------+--------------+--------- - # other | X | X | X + # other(force_reload=false) | X | X | X # other=(other) | X | X | X # build_other(attributes={}) | X | | X # create_other(attributes={}) | X | | X @@ -212,7 +225,7 @@ module ActiveRecord # | | | has_many # generated methods | habtm | has_many | :through # ----------------------------------+-------+----------+---------- - # others | X | X | X + # others(force_reload=false) | X | X | X # others=(other,other,...) | X | X | X # other_ids | X | X | X # other_ids=(id,id,...) | X | X | X @@ -414,6 +427,10 @@ module ActiveRecord # has_many :birthday_events, ->(user) { where starts_on: user.birthday }, class_name: 'Event' # end # + # Note: Joining, eager loading and preloading of these associations is not fully possible. + # These operations happen before instance creation and the scope will be called with a +nil+ argument. + # This can lead to unexpected behavior and is deprecated. + # # == Association callbacks # # Similar to the normal callbacks that hook into the life cycle of an Active Record object, @@ -437,9 +454,11 @@ module ActiveRecord # # Possible callbacks are: +before_add+, +after_add+, +before_remove+ and +after_remove+. # - # Should any of the +before_add+ callbacks throw an exception, the object does not get - # added to the collection. Same with the +before_remove+ callbacks; if an exception is - # thrown the object doesn't get removed. + # If any of the +before_add+ callbacks throw an exception, the object will not be + # added to the collection. + # + # Similarly, if any of the +before_remove+ callbacks throw an exception, the object + # will not be removed from the collection. # # == Association extensions # @@ -531,8 +550,8 @@ module ActiveRecord # end # # @firm = Firm.first - # @firm.clients.collect { |c| c.invoices }.flatten # select all invoices for all clients of the firm - # @firm.invoices # selects all invoices by going through the Client join model + # @firm.clients.flat_map { |c| c.invoices } # select all invoices for all clients of the firm + # @firm.invoices # selects all invoices by going through the Client join model # # Similarly you can go through a +has_one+ association on the join model: # @@ -637,7 +656,7 @@ module ActiveRecord # belongs_to :commenter # end # - # When using nested association, you will not be able to modify the association because there + # When using a 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. @@ -669,11 +688,14 @@ module ActiveRecord # and member posts that use the posts table for STI. In this case, there must be a +type+ # column in the posts table. # + # Note: The <tt>attachable_type=</tt> method is being called when assigning an +attachable+. + # The +class_name+ of the +attachable+ is passed as a String. + # # class Asset < ActiveRecord::Base # belongs_to :attachable, polymorphic: true # - # def attachable_type=(sType) - # super(sType.to_s.classify.constantize.base_class.to_s) + # def attachable_type=(class_name) + # super(class_name.constantize.base_class.to_s) # end # end # @@ -704,9 +726,9 @@ module ActiveRecord # == Eager loading of associations # # Eager loading is a way to find objects of a certain class and a number of named associations. - # This is one of the easiest ways of to prevent the dreaded 1+N problem in which fetching 100 + # It is one of the easiest ways to prevent the dreaded N+1 problem in which fetching 100 # posts that each need to display their author triggers 101 database queries. Through the - # use of eager loading, the 101 queries can be reduced to 2. + # use of eager loading, the number of queries will be reduced from 101 to 2. # # class Post < ActiveRecord::Base # belongs_to :author @@ -736,16 +758,16 @@ module ActiveRecord # Post.includes(:author, :comments).each do |post| # # This will load all comments with a single query. This reduces the total number of queries - # to 3. More generally the number of queries will be 1 plus the number of associations + # to 3. In general, the number of queries will be 1 plus the number of associations # named (except if some of the associations are polymorphic +belongs_to+ - see below). # # To include a deep hierarchy of associations, use a hash: # - # Post.includes(:author, {comments: {author: :gravatar}}).each do |post| + # Post.includes(:author, { comments: { author: :gravatar } }).each do |post| # - # That'll grab not only all the comments but all their authors and gravatar pictures. - # You can mix and match symbols, arrays and hashes in any combination to describe the - # associations you want to load. + # The above code will load all the comments and all of their associated + # authors and gravatars. You can mix and match any combination of symbols, + # arrays, and hashes to retrieve the associations you want to load. # # All of this power shouldn't fool you into thinking that you can pull out huge amounts # of data with no performance penalty just because you've reduced the number of queries. @@ -754,8 +776,8 @@ module ActiveRecord # cut down on the number of queries in a situation as the one described above. # # Since only one table is loaded at a time, conditions or orders cannot reference tables - # other than the main one. If this is the case Active Record falls back to the previously - # used LEFT OUTER JOIN based strategy. For example + # other than the main one. If this is the case, Active Record falls back to the previously + # used LEFT OUTER JOIN based strategy. For example: # # Post.includes([:author, :comments]).where(['comments.approved = ?', true]) # @@ -765,11 +787,16 @@ module ActiveRecord # like this can have unintended consequences. # In the above example posts with no approved comments are not returned at all, because # the conditions apply to the SQL statement as a whole and not just to the association. + # # You must disambiguate column references for this fallback to happen, for example # <tt>order: "author.name DESC"</tt> will work but <tt>order: "name DESC"</tt> will not. # - # If you do want eager load only some members of an association it is usually more natural - # to include an association which has conditions defined on it: + # If you want to load all posts (including posts with no approved comments) then write + # your own LEFT OUTER JOIN query using ON + # + # Post.joins("LEFT OUTER JOIN comments ON comments.post_id = posts.id AND comments.approved = '1'") + # + # In this case it is usually more natural to include an association which has conditions defined on it: # # class Post < ActiveRecord::Base # has_many :approved_comments, -> { where approved: true }, class_name: 'Comment' @@ -1034,6 +1061,9 @@ module ActiveRecord # Specifies a one-to-many association. The following methods for retrieval and query of # collections of associated objects will be added: # + # +collection+ is a placeholder for the symbol passed as the +name+ argument, so + # <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>. + # # [collection(force_reload = false)] # Returns an array of all the associated objects. # An empty array is returned if none are found. @@ -1092,9 +1122,6 @@ module ActiveRecord # Does the same as <tt>collection.create</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt> # if the record is invalid. # - # (*Note*: +collection+ is replaced with the symbol passed as the first argument, so - # <tt>has_many :clients</tt> would add among others <tt>clients.empty?</tt>.) - # # === Example # # A <tt>Firm</tt> class declares <tt>has_many :clients</tt>, which will add: @@ -1113,7 +1140,32 @@ module ActiveRecord # * <tt>Firm#clients.build</tt> (similar to <tt>Client.new("firm_id" => id)</tt>) # * <tt>Firm#clients.create</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save; c</tt>) # * <tt>Firm#clients.create!</tt> (similar to <tt>c = Client.new("firm_id" => id); c.save!</tt>) - # The declaration can also include an options hash to specialize the behavior of the association. + # The declaration can also include an +options+ hash to specialize the behavior of the association. + # + # === Scopes + # + # You can pass a second argument +scope+ as a callable (i.e. proc or + # lambda) to retrieve a specific set of records or customize the generated + # query when you access the associated collection. + # + # Scope examples: + # has_many :comments, -> { where(author_id: 1) } + # has_many :employees, -> { joins(:address) } + # has_many :posts, ->(post) { where("max_post_length > ?", post.length) } + # + # === Extensions + # + # The +extension+ argument allows you to pass a block into a has_many + # association. This is useful for adding new finders, creators and other + # factory-type methods to be used as part of the association. + # + # Extension examples: + # has_many :employees do + # def find_or_create_by_name(name) + # first_name, last_name = name.split(" ", 2) + # find_or_create_by(first_name: first_name, last_name: last_name) + # end + # end # # === Options # [:class_name] @@ -1125,8 +1177,14 @@ module ActiveRecord # Specify the foreign key used for the association. By default this is guessed to be the name # of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_many+ # association will use "person_id" as the default <tt>:foreign_key</tt>. + # [:foreign_type] + # Specify the column used to store the associated object's type, if this is a polymorphic + # association. By default this is guessed to be the name of the polymorphic association + # specified on "as" option with a "_type" suffix. So a class that defines a + # <tt>has_many :tags, as: :taggable</tt> association will use "taggable_type" as the + # default <tt>:foreign_type</tt>. # [:primary_key] - # Specify the method that returns the primary key used for the association. By default this is +id+. + # Specify the name of the column to use as the primary key for the association. By default this is +id+. # [:dependent] # Controls what happens to the associated objects when # their owner is destroyed. Note that these are implemented as @@ -1187,11 +1245,15 @@ module ActiveRecord # that is the inverse of this <tt>has_many</tt> association. Does not work in combination # with <tt>:through</tt> or <tt>:as</tt> options. # See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail. + # [:extend] + # Specifies a module or array of modules that will be extended into the association object returned. + # Useful for defining methods on associations, especially when they should be shared between multiple + # association objects. # # Option examples: # has_many :comments, -> { order "posted_on" } # has_many :comments, -> { includes :author } - # has_many :people, -> { where("deleted = 0").order("name") }, class_name: "Person" + # has_many :people, -> { where(deleted: false).order("name") }, class_name: "Person" # has_many :tracks, -> { order "position" }, dependent: :destroy # has_many :comments, dependent: :nullify # has_many :tags, as: :taggable @@ -1209,11 +1271,15 @@ module ActiveRecord # # The following methods for retrieval and query of a single associated object will be added: # + # +association+ is a placeholder for the symbol passed as the +name+ argument, so + # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>. + # # [association(force_reload = false)] # Returns the associated object. +nil+ is returned if none is found. # [association=(associate)] # Assigns the associate object, extracts the primary key, sets it as the foreign key, - # and saves the associate object. + # and saves the associate object. To avoid database inconsistencies, permanently deletes an existing + # associated object when assigning a new one, even if the new one isn't saved to database. # [build_association(attributes = {})] # Returns a new object of the associated type that has been instantiated # with +attributes+ and linked to this object through a foreign key, but has not @@ -1226,9 +1292,6 @@ module ActiveRecord # Does the same as <tt>create_association</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt> # if the record is invalid. # - # (+association+ is replaced with the symbol passed as the first argument, so - # <tt>has_one :manager</tt> would add among others <tt>manager.nil?</tt>.) - # # === Example # # An Account class declares <tt>has_one :beneficiary</tt>, which will add: @@ -1238,9 +1301,20 @@ module ActiveRecord # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>) # * <tt>Account#create_beneficiary!</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save!; b</tt>) # + # === Scopes + # + # You can pass a second argument +scope+ as a callable (i.e. proc or + # lambda) to retrieve a specific record or customize the generated query + # when you access the associated object. + # + # Scope examples: + # has_one :author, -> { where(comment_id: 1) } + # has_one :employer, -> { joins(:company) } + # has_one :dob, ->(dob) { where("Date.new(2000, 01, 01) > ?", dob) } + # # === Options # - # The declaration can also include an options hash to specialize the behavior of the association. + # The declaration can also include an +options+ hash to specialize the behavior of the association. # # Options are: # [:class_name] @@ -1260,6 +1334,12 @@ module ActiveRecord # Specify the foreign key used for the association. By default this is guessed to be the name # of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_one+ association # will use "person_id" as the default <tt>:foreign_key</tt>. + # [:foreign_type] + # Specify the column used to store the associated object's type, if this is a polymorphic + # association. By default this is guessed to be the name of the polymorphic association + # specified on "as" option with a "_type" suffix. So a class that defines a + # <tt>has_one :tag, as: :taggable</tt> association will use "taggable_type" as the + # default <tt>:foreign_type</tt>. # [:primary_key] # Specify the method that returns the primary key used for the association. By default this is +id+. # [:as] @@ -1290,6 +1370,10 @@ module ActiveRecord # that is the inverse of this <tt>has_one</tt> association. Does not work in combination # with <tt>:through</tt> or <tt>:as</tt> options. # See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail. + # [:required] + # When set to +true+, the association will also have its presence validated. + # This will validate the association itself, not the id. You can use + # +:inverse_of+ to avoid an extra query during validation. # # Option examples: # has_one :credit_card, dependent: :destroy # destroys the associated credit card @@ -1301,6 +1385,7 @@ module ActiveRecord # has_one :boss, readonly: :true # has_one :club, through: :membership # has_one :primary_address, -> { where primary: true }, through: :addressables, source: :addressable + # has_one :credit_card, required: true def has_one(name, scope = nil, options = {}) reflection = Builder::HasOne.build(self, name, scope, options) Reflection.add_reflection self, name, reflection @@ -1314,6 +1399,9 @@ module ActiveRecord # Methods will be added for retrieval and query for a single associated object, for which # this object holds an id: # + # +association+ is a placeholder for the symbol passed as the +name+ argument, so + # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>. + # # [association(force_reload = false)] # Returns the associated object. +nil+ is returned if none is found. # [association=(associate)] @@ -1329,9 +1417,6 @@ module ActiveRecord # Does the same as <tt>create_association</tt>, but raises <tt>ActiveRecord::RecordInvalid</tt> # if the record is invalid. # - # (+association+ is replaced with the symbol passed as the first argument, so - # <tt>belongs_to :author</tt> would add among others <tt>author.nil?</tt>.) - # # === Example # # A Post class declares <tt>belongs_to :author</tt>, which will add: @@ -1340,7 +1425,18 @@ module ActiveRecord # * <tt>Post#build_author</tt> (similar to <tt>post.author = Author.new</tt>) # * <tt>Post#create_author</tt> (similar to <tt>post.author = Author.new; post.author.save; post.author</tt>) # * <tt>Post#create_author!</tt> (similar to <tt>post.author = Author.new; post.author.save!; post.author</tt>) - # The declaration can also include an options hash to specialize the behavior of the association. + # The declaration can also include an +options+ hash to specialize the behavior of the association. + # + # === Scopes + # + # You can pass a second argument +scope+ as a callable (i.e. proc or + # lambda) to retrieve a specific record or customize the generated query + # when you access the associated object. + # + # Scope examples: + # belongs_to :user, -> { where(id: 2) } + # belongs_to :user, -> { joins(:friends) } + # belongs_to :level, ->(level) { where("game_level > ?", level.current) } # # === Options # @@ -1394,7 +1490,7 @@ module ActiveRecord # # Note that <tt>accepts_nested_attributes_for</tt> sets <tt>:autosave</tt> to <tt>true</tt>. # [:touch] - # If true, the associated object will be touched (the updated_at/on attributes set to now) + # If true, the associated object will be touched (the updated_at/on attributes set to current time) # when this record is either saved or destroyed. If you specify a symbol, that attribute # will be updated with the current time in addition to the updated_at/on attribute. # [:inverse_of] @@ -1402,18 +1498,23 @@ module ActiveRecord # object that is the inverse of this <tt>belongs_to</tt> association. Does not work in # combination with the <tt>:polymorphic</tt> options. # See ActiveRecord::Associations::ClassMethods's overview on Bi-directional associations for more detail. + # [:required] + # When set to +true+, the association will also have its presence validated. + # This will validate the association itself, not the id. You can use + # +:inverse_of+ to avoid an extra query during validation. # # Option examples: # belongs_to :firm, foreign_key: "client_of" # belongs_to :person, primary_key: "name", foreign_key: "person_name" # belongs_to :author, class_name: "Person", foreign_key: "author_id" - # belongs_to :valid_coupon, ->(o) { where "discounts > #{o.payments_count}" }, + # belongs_to :valid_coupon, ->(o) { where "discounts > ?", o.payments_count }, # class_name: "Coupon", foreign_key: "coupon_id" # belongs_to :attachable, polymorphic: true # belongs_to :project, readonly: true # belongs_to :post, counter_cache: true # belongs_to :company, touch: true # belongs_to :company, touch: :employees_last_updated_at + # belongs_to :company, required: true def belongs_to(name, scope = nil, options = {}) reflection = Builder::BelongsTo.build(self, name, scope, options) Reflection.add_reflection self, name, reflection @@ -1451,6 +1552,9 @@ module ActiveRecord # # Adds the following methods for retrieval and query: # + # +collection+ is a placeholder for the symbol passed as the +name+ argument, so + # <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>. + # # [collection(force_reload = false)] # Returns an array of all the associated objects. # An empty array is returned if none are found. @@ -1492,9 +1596,6 @@ module ActiveRecord # with +attributes+, linked to this object through the join table, and that has already been # saved (if it passed the validation). # - # (+collection+ is replaced with the symbol passed as the first argument, so - # <tt>has_and_belongs_to_many :categories</tt> would add among others <tt>categories.empty?</tt>.) - # # === Example # # A Developer class declares <tt>has_and_belongs_to_many :projects</tt>, which will add: @@ -1512,7 +1613,34 @@ module ActiveRecord # * <tt>Developer#projects.exists?(...)</tt> # * <tt>Developer#projects.build</tt> (similar to <tt>Project.new("developer_id" => id)</tt>) # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new("developer_id" => id); c.save; c</tt>) - # The declaration may include an options hash to specialize the behavior of the association. + # The declaration may include an +options+ hash to specialize the behavior of the association. + # + # === Scopes + # + # You can pass a second argument +scope+ as a callable (i.e. proc or + # lambda) to retrieve a specific set of records or customize the generated + # query when you access the associated collection. + # + # Scope examples: + # has_and_belongs_to_many :projects, -> { includes :milestones, :manager } + # has_and_belongs_to_many :categories, ->(category) { + # where("default_category = ?", category.name) + # } + # + # === Extensions + # + # The +extension+ argument allows you to pass a block into a + # has_and_belongs_to_many association. This is useful for adding new + # finders, creators and other factory-type methods to be used as part of + # the association. + # + # Extension examples: + # has_and_belongs_to_many :contractors do + # def find_or_create_by_name(name) + # first_name, last_name = name.split(" ", 2) + # find_or_create_by(first_name: first_name, last_name: last_name) + # end + # end # # === Options # @@ -1558,14 +1686,22 @@ module ActiveRecord scope = nil end + habtm_reflection = ActiveRecord::Reflection::HasAndBelongsToManyReflection.new(name, scope, options, self) + builder = Builder::HasAndBelongsToMany.new name, self, options join_model = builder.through_model + # FIXME: we should move this to the internal constants. Also people + # should never directly access this constant so I'm not happy about + # setting it. + const_set join_model.name, join_model + middle_reflection = builder.middle_reflection join_model Builder::HasMany.define_callbacks self, middle_reflection Reflection.add_reflection self, middle_reflection.name, middle_reflection + middle_reflection.parent_reflection = [name.to_s, habtm_reflection] include Module.new { class_eval <<-RUBY, __FILE__, __LINE__ + 1 @@ -1581,11 +1717,12 @@ module ActiveRecord hm_options[:through] = middle_reflection.name hm_options[:source] = join_model.right_reflection.name - [:before_add, :after_add, :before_remove, :after_remove].each do |k| + [:before_add, :after_add, :before_remove, :after_remove, :autosave, :validate, :join_table, :class_name].each do |k| hm_options[k] = options[k] if options.key? k end has_many name, scope, hm_options, &extension + self._reflections[name.to_s].parent_reflection = [name.to_s, habtm_reflection] end end end |