+++ /dev/null
-module ActiveRecord
- class HasManyThroughAssociationNotFoundError < ActiveRecordError #:nodoc:
- def initialize(owner_class_name, reflection)
- super("Could not find the association #{reflection.options[:through].inspect} in model #{owner_class_name}")
- end
- end
-
- class HasManyThroughAssociationPolymorphicError < ActiveRecordError #:nodoc:
- def initialize(owner_class_name, reflection, source_reflection)
- super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' on the polymorphic object '#{source_reflection.class_name}##{source_reflection.name}'.")
- end
- end
-
- class HasManyThroughAssociationPointlessSourceTypeError < ActiveRecordError #:nodoc:
- def initialize(owner_class_name, reflection, source_reflection)
- super("Cannot have a has_many :through association '#{owner_class_name}##{reflection.name}' with a :source_type option if the '#{reflection.through_reflection.class_name}##{source_reflection.name}' is not polymorphic. Try removing :source_type on your association.")
- 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(&: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
-
- 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}.")
- end
- end
- HasManyThroughCantAssociateThroughHasManyReflection = ActiveSupport::Deprecation::DeprecatedConstantProxy.new('ActiveRecord::HasManyThroughCantAssociateThroughHasManyReflection', 'ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection')
-
- 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.")
- end
- end
-
- class HasManyThroughCantDissociateNewRecords < ActiveRecordError #:nodoc:
- def initialize(owner, reflection)
- 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 HasAndBelongsToManyAssociationForeignKeyNeeded < ActiveRecordError #:nodoc:
- def initialize(reflection)
- super("Cannot create self referential has_and_belongs_to_many association on '#{reflection.class_name rescue nil}##{reflection.name rescue nil}'. :association_foreign_key cannot be the same as the :foreign_key.")
- end
- end
-
- class EagerLoadPolymorphicError < ActiveRecordError #:nodoc:
- def initialize(reflection)
- super("Can not eagerly load the polymorphic association #{reflection.name.inspect}")
- end
- end
-
- class ReadOnlyAssociation < ActiveRecordError #:nodoc:
- def initialize(reflection)
- super("Can not add to a has_many :through association. Try adding to #{reflection.through_reflection.name.inspect}.")
- end
- end
-
- # See ActiveRecord::Associations::ClassMethods for documentation.
- module Associations # :nodoc:
- # These classes will be loaded when associations are created.
- # So there is no need to eager load them.
- autoload :AssociationCollection, 'active_record/associations/association_collection'
- autoload :AssociationProxy, 'active_record/associations/association_proxy'
- autoload :BelongsToAssociation, 'active_record/associations/belongs_to_association'
- autoload :BelongsToPolymorphicAssociation, 'active_record/associations/belongs_to_polymorphic_association'
- autoload :HasAndBelongsToManyAssociation, 'active_record/associations/has_and_belongs_to_many_association'
- autoload :HasManyAssociation, 'active_record/associations/has_many_association'
- 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'
-
- def self.included(base)
- base.extend(ClassMethods)
- end
-
- # Clears out the association cache
- def clear_association_cache #:nodoc:
- self.class.reflect_on_all_associations.to_a.each do |assoc|
- instance_variable_set "@#{assoc.name}", nil
- end unless self.new_record?
- end
-
- private
- # Gets the specified association instance if it responds to :loaded?, nil otherwise.
- def association_instance_get(name)
- association = instance_variable_get("@#{name}")
- association if association.respond_to?(:loaded?)
- end
-
- # Set the specified association instance.
- def association_instance_set(name, association)
- instance_variable_set("@#{name}", association)
- end
-
- # Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like
- # "Project has one Project Manager" or "Project belongs to a Portfolio". Each macro adds a number of methods to the class which are
- # specialized according to the collection or association symbol and the options hash. It works much the same way as Ruby's own <tt>attr*</tt>
- # methods. Example:
- #
- # class Project < ActiveRecord::Base
- # belongs_to :portfolio
- # has_one :project_manager
- # has_many :milestones
- # has_and_belongs_to_many :categories
- # end
- #
- # The project class now has the following methods (and more) to ease the traversal and manipulation of its relationships:
- # * <tt>Project#portfolio, Project#portfolio=(portfolio), Project#portfolio.nil?</tt>
- # * <tt>Project#project_manager, Project#project_manager=(project_manager), Project#project_manager.nil?,</tt>
- # * <tt>Project#milestones.empty?, Project#milestones.size, Project#milestones, Project#milestones<<(milestone),</tt>
- # <tt>Project#milestones.delete(milestone), Project#milestones.find(milestone_id), Project#milestones.find(:all, options),</tt>
- # <tt>Project#milestones.build, Project#milestones.create</tt>
- # * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt>
- # <tt>Project#categories.delete(category1)</tt>
- #
- # === A word of warning
- #
- # Don't create associations that have the same name as instance methods of ActiveRecord::Base. Since the association
- # adds a method with that name to its model, it will override the inherited method and break things.
- # For instance, +attributes+ and +connection+ would be bad choices for association names.
- #
- # == Auto-generated methods
- #
- # === Singular associations (one-to-one)
- # | | belongs_to |
- # generated methods | belongs_to | :polymorphic | has_one
- # ----------------------------------+------------+--------------+---------
- # other | X | X | X
- # other=(other) | X | X | X
- # build_other(attributes={}) | X | | X
- # create_other(attributes={}) | X | | X
- # other.create!(attributes={}) | | | X
- #
- # ===Collection associations (one-to-many / many-to-many)
- # | | | has_many
- # generated methods | habtm | has_many | :through
- # ----------------------------------+-------+----------+----------
- # others | X | X | X
- # others=(other,other,...) | X | X | X
- # other_ids | X | X | X
- # other_ids=(id,id,...) | X | X | X
- # others<< | X | X | X
- # others.push | X | X | X
- # others.concat | X | X | X
- # others.build(attributes={}) | X | X | X
- # others.create(attributes={}) | X | X | X
- # others.create!(attributes={}) | X | X | X
- # others.size | X | X | X
- # others.length | X | X | X
- # others.count | X | X | X
- # others.sum(args*,&block) | X | X | X
- # others.empty? | X | X | X
- # others.clear | X | X | X
- # others.delete(other,other,...) | X | X | X
- # others.delete_all | X | X |
- # others.destroy_all | X | X | X
- # others.find(*args) | X | X | X
- # others.find_first | X | |
- # others.exists? | X | X | X
- # others.uniq | X | X | X
- # others.reset | X | X | X
- #
- # == Cardinality and associations
- #
- # Active Record associations can be used to describe one-to-one, one-to-many and many-to-many
- # relationships between models. Each model uses an association to describe its role in
- # the relation. The +belongs_to+ association is always used in the model that has
- # the foreign key.
- #
- # === One-to-one
- #
- # Use +has_one+ in the base, and +belongs_to+ in the associated model.
- #
- # class Employee < ActiveRecord::Base
- # has_one :office
- # end
- # class Office < ActiveRecord::Base
- # belongs_to :employee # foreign key - employee_id
- # end
- #
- # === One-to-many
- #
- # Use +has_many+ in the base, and +belongs_to+ in the associated model.
- #
- # class Manager < ActiveRecord::Base
- # has_many :employees
- # end
- # class Employee < ActiveRecord::Base
- # belongs_to :manager # foreign key - manager_id
- # end
- #
- # === Many-to-many
- #
- # There are two ways to build a many-to-many relationship.
- #
- # The first way uses a +has_many+ association with the <tt>:through</tt> option and a join model, so
- # there are two stages of associations.
- #
- # class Assignment < ActiveRecord::Base
- # belongs_to :programmer # foreign key - programmer_id
- # belongs_to :project # foreign key - project_id
- # end
- # class Programmer < ActiveRecord::Base
- # has_many :assignments
- # has_many :projects, :through => :assignments
- # end
- # class Project < ActiveRecord::Base
- # has_many :assignments
- # has_many :programmers, :through => :assignments
- # end
- #
- # For the second way, use +has_and_belongs_to_many+ in both models. This requires a join table
- # that has no corresponding model or primary key.
- #
- # class Programmer < ActiveRecord::Base
- # has_and_belongs_to_many :projects # foreign keys in the join table
- # end
- # class Project < ActiveRecord::Base
- # has_and_belongs_to_many :programmers # foreign keys in the join table
- # end
- #
- # Choosing which way to build a many-to-many relationship is not always simple.
- # If you need to work with the relationship model as its own entity,
- # use <tt>has_many :through</tt>. Use +has_and_belongs_to_many+ when working with legacy schemas or when
- # you never work directly with the relationship itself.
- #
- # == Is it a +belongs_to+ or +has_one+ association?
- #
- # Both express a 1-1 relationship. The difference is mostly where to place the foreign key, which goes on the table for the class
- # declaring the +belongs_to+ relationship. Example:
- #
- # class User < ActiveRecord::Base
- # # I reference an account.
- # belongs_to :account
- # end
- #
- # class Account < ActiveRecord::Base
- # # One user references me.
- # has_one :user
- # end
- #
- # The tables for these classes could look something like:
- #
- # CREATE TABLE users (
- # id int(11) NOT NULL auto_increment,
- # account_id int(11) default NULL,
- # name varchar default NULL,
- # PRIMARY KEY (id)
- # )
- #
- # CREATE TABLE accounts (
- # id int(11) NOT NULL auto_increment,
- # name varchar default NULL,
- # PRIMARY KEY (id)
- # )
- #
- # == Unsaved objects and associations
- #
- # You can manipulate objects and associations before they are saved to the database, but there is some special behavior you should be
- # aware of, mostly involving the saving of associated objects.
- #
- # Unless you set the :autosave option on a <tt>has_one</tt>, <tt>belongs_to</tt>,
- # <tt>has_many</tt>, or <tt>has_and_belongs_to_many</tt> association. Setting it
- # to +true+ will _always_ save the members, whereas setting it to +false+ will
- # _never_ save the members.
- #
- # === One-to-one associations
- #
- # * Assigning an object to a +has_one+ association automatically saves that object and the object being replaced (if there is one), in
- # order to update their primary keys - except if the parent object is unsaved (<tt>new_record? == true</tt>).
- # * If either of these saves fail (due to one of the objects being invalid) the assignment statement returns +false+ and the assignment
- # is cancelled.
- # * If you wish to assign an object to a +has_one+ association without saving it, use the <tt>association.build</tt> method (documented below).
- # * Assigning an object to a +belongs_to+ association does not save the object, since the foreign key field belongs on the parent. It
- # does not save the parent either.
- #
- # === Collections
- #
- # * Adding an object to a collection (+has_many+ or +has_and_belongs_to_many+) automatically saves that object, except if the parent object
- # (the owner of the collection) is not yet stored in the database.
- # * If saving any of the objects being added to a collection (via <tt>push</tt> or similar) fails, then <tt>push</tt> returns +false+.
- # * You can add an object to a collection without automatically saving it by using the <tt>collection.build</tt> method (documented below).
- # * All unsaved (<tt>new_record? == true</tt>) members of the collection are automatically saved when the parent is saved.
- #
- # === Association callbacks
- #
- # Similar to the normal callbacks that hook into the lifecycle of an Active Record object, you can also define callbacks that get
- # triggered when you add an object to or remove an object from an association collection. Example:
- #
- # class Project
- # has_and_belongs_to_many :developers, :after_add => :evaluate_velocity
- #
- # def evaluate_velocity(developer)
- # ...
- # end
- # end
- #
- # It's possible to stack callbacks by passing them as an array. Example:
- #
- # class Project
- # has_and_belongs_to_many :developers, :after_add => [:evaluate_velocity, Proc.new { |p, d| p.shipping_date = Time.now}]
- # end
- #
- # 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.
- #
- # === Association extensions
- #
- # The proxy objects that control the access to associations can be extended through anonymous modules. This is especially
- # beneficial for adding new finders, creators, and other factory-type methods that are only used as part of this association.
- # Example:
- #
- # class Account < ActiveRecord::Base
- # has_many :people do
- # def find_or_create_by_name(name)
- # first_name, last_name = name.split(" ", 2)
- # find_or_create_by_first_name_and_last_name(first_name, last_name)
- # end
- # end
- # end
- #
- # person = Account.find(:first).people.find_or_create_by_name("David Heinemeier Hansson")
- # person.first_name # => "David"
- # person.last_name # => "Heinemeier Hansson"
- #
- # If you need to share the same extensions between many associations, you can use a named extension module. Example:
- #
- # module FindOrCreateByNameExtension
- # def find_or_create_by_name(name)
- # first_name, last_name = name.split(" ", 2)
- # find_or_create_by_first_name_and_last_name(first_name, last_name)
- # end
- # end
- #
- # class Account < ActiveRecord::Base
- # has_many :people, :extend => FindOrCreateByNameExtension
- # end
- #
- # class Company < ActiveRecord::Base
- # has_many :people, :extend => FindOrCreateByNameExtension
- # end
- #
- # If you need to use multiple named extension modules, you can specify an array of modules with the <tt>:extend</tt> option.
- # In the case of name conflicts between methods in the modules, methods in modules later in the array supercede
- # those earlier in the array. Example:
- #
- # class Account < ActiveRecord::Base
- # has_many :people, :extend => [FindOrCreateByNameExtension, FindRecentExtension]
- # end
- #
- # Some extensions can only be made to work with knowledge of the association proxy's internals.
- # Extensions can access relevant state using accessors on the association proxy:
- #
- # * +proxy_owner+ - Returns the object the association is part of.
- # * +proxy_reflection+ - Returns the reflection object that describes the association.
- # * +proxy_target+ - Returns the associated object for +belongs_to+ and +has_one+, or the collection of associated objects for +has_many+ and +has_and_belongs_to_many+.
- #
- # === Association Join Models
- #
- # Has Many associations can be configured with the <tt>:through</tt> option to use an explicit join model to retrieve the data. This
- # operates similarly to a +has_and_belongs_to_many+ association. The advantage is that you're able to add validations,
- # callbacks, and extra attributes on the join model. Consider the following schema:
- #
- # class Author < ActiveRecord::Base
- # has_many :authorships
- # has_many :books, :through => :authorships
- # end
- #
- # class Authorship < ActiveRecord::Base
- # belongs_to :author
- # belongs_to :book
- # end
- #
- # @author = Author.find :first
- # @author.authorships.collect { |a| a.book } # selects all books that the author's authorships belong to.
- # @author.books # selects all books by using the Authorship join model
- #
- # You can also go through a +has_many+ association on the join model:
- #
- # class Firm < ActiveRecord::Base
- # has_many :clients
- # has_many :invoices, :through => :clients
- # end
- #
- # class Client < ActiveRecord::Base
- # belongs_to :firm
- # has_many :invoices
- # end
- #
- # class Invoice < ActiveRecord::Base
- # belongs_to :client
- # end
- #
- # @firm = Firm.find :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.
- #
- # Similarly you can go through a +has_one+ association on the join model:
- #
- # class Group < ActiveRecord::Base
- # has_many :users
- # has_many :avatars, :through => :users
- # end
- #
- # class User < ActiveRecord::Base
- # belongs_to :group
- # has_one :avatar
- # end
- #
- # class Avatar < ActiveRecord::Base
- # belongs_to :user
- # end
- #
- # @group = Group.first
- # @group.users.collect { |u| u.avatar }.flatten # select all avatars for all users in the group
- # @group.avatars # selects all avatars by going through the User join model.
- #
- # An important caveat with going through +has_one+ or +has_many+ associations on the join model is that these associations are
- # *read-only*. For example, the following would not work following the previous example:
- #
- # @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
- #
- # === Polymorphic Associations
- #
- # Polymorphic associations on models are not restricted on what types of models they can be associated with. Rather, they
- # specify an interface that a +has_many+ association must adhere to.
- #
- # class Asset < ActiveRecord::Base
- # belongs_to :attachable, :polymorphic => true
- # end
- #
- # class Post < ActiveRecord::Base
- # has_many :assets, :as => :attachable # The :as option specifies the polymorphic interface to use.
- # end
- #
- # @asset.attachable = @post
- #
- # This works by using a type column in addition to a foreign key to specify the associated record. In the Asset example, you'd need
- # an +attachable_id+ integer column and an +attachable_type+ string column.
- #
- # Using polymorphic associations in combination with single table inheritance (STI) is a little tricky. In order
- # for the associations to work as expected, ensure that you store the base model for the STI models in the
- # type column of the polymorphic association. To continue with the asset example above, suppose there are guest posts
- # and member posts that use the posts table for STI. In this case, there must be a +type+ column in the posts table.
- #
- # class Asset < ActiveRecord::Base
- # belongs_to :attachable, :polymorphic => true
- #
- # def attachable_type=(sType)
- # super(sType.to_s.classify.constantize.base_class.to_s)
- # end
- # end
- #
- # class Post < ActiveRecord::Base
- # # because we store "Post" in attachable_type now :dependent => :destroy will work
- # has_many :assets, :as => :attachable, :dependent => :destroy
- # end
- #
- # class GuestPost < Post
- # end
- #
- # class MemberPost < Post
- # end
- #
- # == Caching
- #
- # All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically
- # instructed not to. The cache is even shared across methods to make it even cheaper to use the macro-added methods without
- # worrying too much about performance at the first go. Example:
- #
- # project.milestones # fetches milestones from the database
- # project.milestones.size # uses the milestone cache
- # project.milestones.empty? # uses the milestone cache
- # project.milestones(true).size # fetches milestones from the database
- # project.milestones # uses the milestone cache
- #
- # == 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 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. Example:
- #
- # class Post < ActiveRecord::Base
- # belongs_to :author
- # has_many :comments
- # end
- #
- # Consider the following loop using the class above:
- #
- # for post in Post.all
- # puts "Post: " + post.title
- # puts "Written by: " + post.author.name
- # puts "Last comment on: " + post.comments.first.created_on
- # end
- #
- # To iterate over these one hundred posts, we'll generate 201 database queries. Let's first just optimize it for retrieving the author:
- #
- # for post in Post.find(:all, :include => :author)
- #
- # This references the name of the +belongs_to+ association that also used the <tt>:author</tt> symbol. After loading the posts, find
- # will collect the +author_id+ from each one and load all the referenced authors with one query. Doing so will cut down the number of queries from 201 to 102.
- #
- # We can improve upon the situation further by referencing both associations in the finder with:
- #
- # for post in Post.find(:all, :include => [ :author, :comments ])
- #
- # 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 named (except if some of the associations are polymorphic +belongs_to+ - see below).
- #
- # To include a deep hierarchy of associations, use a hash:
- #
- # for post in Post.find(:all, :include => [ :author, { :comments => { :author => :gravatar } } ])
- #
- # 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.
- #
- # 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. The database still needs to send all the data to Active Record and it still needs to be processed. So it's no
- # catch-all for performance problems, but it's a great way to 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
- #
- # Post.find(:all, :include => [ :author, :comments ], :conditions => ['comments.approved = ?', true])
- #
- # will result in a single SQL query with joins along the lines of: <tt>LEFT OUTER JOIN comments ON comments.post_id = posts.id</tt> and
- # <tt>LEFT OUTER JOIN authors ON authors.id = posts.author_id</tt>. Note that using conditions 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 eagerload only some members of an association it is usually more natural to <tt>:include</tt> an association
- # which has conditions defined on it:
- #
- # class Post < ActiveRecord::Base
- # has_many :approved_comments, :class_name => 'Comment', :conditions => ['approved = ?', true]
- # end
- #
- # Post.find(:all, :include => :approved_comments)
- #
- # will load posts and eager load the +approved_comments+ association, which contains only those comments that have been approved.
- #
- # If you eager load an association with a specified <tt>:limit</tt> option, it will be ignored, returning all the associated objects:
- #
- # class Picture < ActiveRecord::Base
- # has_many :most_recent_comments, :class_name => 'Comment', :order => 'id DESC', :limit => 10
- # end
- #
- # Picture.find(:first, :include => :most_recent_comments).most_recent_comments # => returns all associated comments.
- #
- # When eager loaded, conditions are interpolated in the context of the model class, not the model instance. Conditions are lazily interpolated
- # before the actual model exists.
- #
- # Eager loading is supported with polymorphic associations.
- #
- # class Address < ActiveRecord::Base
- # belongs_to :addressable, :polymorphic => true
- # end
- #
- # A call that tries to eager load the addressable model
- #
- # Address.find(:all, :include => :addressable)
- #
- # will execute one query to load the addresses and load the addressables with one query per addressable type.
- # For example if all the addressables are either of class Person or Company then a total of 3 queries will be executed. The list of
- # addressable types to load is determined on the back of the addresses loaded. This is not supported if Active Record has to fallback
- # to the previous implementation of eager loading and will raise ActiveRecord::EagerLoadPolymorphicError. The reason is that the parent
- # model's type is a column value so its corresponding table name cannot be put in the +FROM+/+JOIN+ clauses of that query.
- #
- # == Table Aliasing
- #
- # Active Record uses table aliasing in the case that a table is referenced multiple times in a join. If a table is referenced only once,
- # the standard table name is used. The second time, the table is aliased as <tt>#{reflection_name}_#{parent_table_name}</tt>. Indexes are appended
- # for any more successive uses of the table name.
- #
- # Post.find :all, :joins => :comments
- # # => SELECT ... FROM posts INNER JOIN comments ON ...
- # Post.find :all, :joins => :special_comments # STI
- # # => SELECT ... FROM posts INNER JOIN comments ON ... AND comments.type = 'SpecialComment'
- # Post.find :all, :joins => [:comments, :special_comments] # special_comments is the reflection name, posts is the parent table name
- # # => SELECT ... FROM posts INNER JOIN comments ON ... INNER JOIN comments special_comments_posts
- #
- # Acts as tree example:
- #
- # TreeMixin.find :all, :joins => :children
- # # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
- # TreeMixin.find :all, :joins => {:children => :parent}
- # # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
- # INNER JOIN parents_mixins ...
- # TreeMixin.find :all, :joins => {:children => {:parent => :children}}
- # # => SELECT ... FROM mixins INNER JOIN mixins childrens_mixins ...
- # INNER JOIN parents_mixins ...
- # INNER JOIN mixins childrens_mixins_2
- #
- # Has and Belongs to Many join tables use the same idea, but add a <tt>_join</tt> suffix:
- #
- # Post.find :all, :joins => :categories
- # # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
- # Post.find :all, :joins => {:categories => :posts}
- # # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
- # INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
- # Post.find :all, :joins => {:categories => {:posts => :categories}}
- # # => SELECT ... FROM posts INNER JOIN categories_posts ... INNER JOIN categories ...
- # INNER JOIN categories_posts posts_categories_join INNER JOIN posts posts_categories
- # INNER JOIN categories_posts categories_posts_join INNER JOIN categories categories_posts_2
- #
- # If you wish to specify your own custom joins using a <tt>:joins</tt> option, those table names will take precedence over the eager associations:
- #
- # Post.find :all, :joins => :comments, :joins => "inner join comments ..."
- # # => SELECT ... FROM posts INNER JOIN comments_posts ON ... INNER JOIN comments ...
- # Post.find :all, :joins => [:comments, :special_comments], :joins => "inner join comments ..."
- # # => SELECT ... FROM posts INNER JOIN comments comments_posts ON ...
- # INNER JOIN comments special_comments_posts ...
- # INNER JOIN comments ...
- #
- # Table aliases are automatically truncated according to the maximum length of table identifiers according to the specific database.
- #
- # == Modules
- #
- # By default, associations will look for objects within the current module scope. Consider:
- #
- # module MyApplication
- # module Business
- # class Firm < ActiveRecord::Base
- # has_many :clients
- # end
- #
- # class Client < ActiveRecord::Base; end
- # end
- # end
- #
- # When <tt>Firm#clients</tt> is called, it will in turn call <tt>MyApplication::Business::Client.find_all_by_firm_id(firm.id)</tt>.
- # If you want to associate with a class in another module scope, this can be done by specifying the complete class name.
- # Example:
- #
- # module MyApplication
- # module Business
- # class Firm < ActiveRecord::Base; end
- # end
- #
- # module Billing
- # class Account < ActiveRecord::Base
- # belongs_to :firm, :class_name => "MyApplication::Business::Firm"
- # end
- # end
- # end
- #
- # == Type safety with <tt>ActiveRecord::AssociationTypeMismatch</tt>
- #
- # If you attempt to assign an object to an association that doesn't match the inferred or specified <tt>:class_name</tt>, you'll
- # get an <tt>ActiveRecord::AssociationTypeMismatch</tt>.
- #
- # == Options
- #
- # All of the association macros can be specialized through options. This makes cases more complex than the simple and guessable ones
- # possible.
- module ClassMethods
- # Specifies a one-to-many association. The following methods for retrieval and query of
- # collections of associated objects will be added:
- #
- # [collection(force_reload = false)]
- # Returns an array of all the associated objects.
- # An empty array is returned if none are found.
- # [collection<<(object, ...)]
- # Adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
- # [collection.delete(object, ...)]
- # Removes one or more objects from the collection by setting their foreign keys to +NULL+.
- # Objects will be in addition destroyed if they're associated with <tt>:dependent => :destroy</tt>,
- # and deleted if they're associated with <tt>:dependent => :delete_all</tt>.
- # [collection=objects]
- # Replaces the collections content by deleting and adding objects as appropriate.
- # [collection_singular_ids]
- # Returns an array of the associated objects' ids
- # [collection_singular_ids=ids]
- # Replace the collection with the objects identified by the primary keys in +ids+
- # [collection.clear]
- # Removes every object from the collection. This destroys the associated objects if they
- # are associated with <tt>:dependent => :destroy</tt>, deletes them directly from the
- # database if <tt>:dependent => :delete_all</tt>, otherwise sets their foreign keys to +NULL+.
- # [collection.empty?]
- # Returns +true+ if there are no associated objects.
- # [collection.size]
- # Returns the number of associated objects.
- # [collection.find(...)]
- # Finds an associated object according to the same rules as ActiveRecord::Base.find.
- # [collection.exists?(...)]
- # Checks whether an associated object with the given conditions exists.
- # Uses the same rules as ActiveRecord::Base.exists?.
- # [collection.build(attributes = {}, ...)]
- # Returns one or more new objects of the collection type that have been instantiated
- # with +attributes+ and linked to this object through a foreign key, but have not yet
- # been saved. <b>Note:</b> This only works if an associated object already exists, not if
- # it's +nil+!
- # [collection.create(attributes = {})]
- # Returns a new object of the collection type that has been instantiated
- # with +attributes+, linked to this object through a foreign key, and that has already
- # been saved (if it passed the validation). <b>Note:</b> This only works if an associated
- # object already exists, not if it's +nil+!
- #
- # (*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
- #
- # Example: A Firm class declares <tt>has_many :clients</tt>, which will add:
- # * <tt>Firm#clients</tt> (similar to <tt>Clients.find :all, :conditions => ["firm_id = ?", id]</tt>)
- # * <tt>Firm#clients<<</tt>
- # * <tt>Firm#clients.delete</tt>
- # * <tt>Firm#clients=</tt>
- # * <tt>Firm#client_ids</tt>
- # * <tt>Firm#client_ids=</tt>
- # * <tt>Firm#clients.clear</tt>
- # * <tt>Firm#clients.empty?</tt> (similar to <tt>firm.clients.size == 0</tt>)
- # * <tt>Firm#clients.size</tt> (similar to <tt>Client.count "firm_id = #{id}"</tt>)
- # * <tt>Firm#clients.find</tt> (similar to <tt>Client.find(id, :conditions => "firm_id = #{id}")</tt>)
- # * <tt>Firm#clients.exists?(:name => 'ACME')</tt> (similar to <tt>Client.exists?(:name => 'ACME', :firm_id => firm.id)</tt>)
- # * <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>)
- # The declaration can also include an options hash to specialize the behavior of the association.
- #
- # === Supported options
- # [:class_name]
- # Specify the class name of the association. Use it only if that name can't be inferred
- # from the association name. So <tt>has_many :products</tt> will by default be linked to the Product class, but
- # if the real class name is SpecialProduct, you'll have to specify it with this option.
- # [:conditions]
- # Specify the conditions that the associated objects must meet in order to be included as a +WHERE+
- # SQL fragment, such as <tt>price > 5 AND name LIKE 'B%'</tt>. Record creations from the association are scoped if a hash
- # is used. <tt>has_many :posts, :conditions => {:published => true}</tt> will create published posts with <tt>@blog.posts.create</tt>
- # or <tt>@blog.posts.build</tt>.
- # [:order]
- # Specify the order in which the associated objects are returned as an <tt>ORDER BY</tt> SQL fragment,
- # such as <tt>last_name, first_name DESC</tt>.
- # [:foreign_key]
- # 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>.
- # [:primary_key]
- # Specify the method that returns the primary key used for the association. By default this is +id+.
- # [:dependent]
- # If set to <tt>:destroy</tt> all the associated objects are destroyed
- # alongside this object by calling their +destroy+ method. If set to <tt>:delete_all</tt> all associated
- # objects are deleted *without* calling their +destroy+ method. If set to <tt>:nullify</tt> all associated
- # objects' foreign keys are set to +NULL+ *without* calling their +save+ callbacks. *Warning:* This option is ignored when also using
- # the <tt>:through</tt> option.
- # [:finder_sql]
- # Specify a complete SQL statement to fetch the association. This is a good way to go for complex
- # associations that depend on multiple tables. Note: When this option is used, +find_in_collection+ is _not_ added.
- # [:counter_sql]
- # Specify a complete SQL statement to fetch the size of the association. If <tt>:finder_sql</tt> is
- # specified but not <tt>:counter_sql</tt>, <tt>:counter_sql</tt> will be generated by replacing <tt>SELECT ... FROM</tt> with <tt>SELECT COUNT(*) FROM</tt>.
- # [:extend]
- # Specify a named module for extending the proxy. See "Association extensions".
- # [:include]
- # Specify second-order associations that should be eager loaded when the collection is loaded.
- # [:group]
- # An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
- # [:having]
- # Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
- # [:limit]
- # An integer determining the limit on the number of rows that should be returned.
- # [:offset]
- # An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
- # [:select]
- # By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if you, for example, 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.
- # [: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.
- # [:source]
- # Specifies the source association name used by <tt>has_many :through</tt> queries. Only use it if the name cannot be
- # inferred from the association. <tt>has_many :subscribers, :through => :subscriptions</tt> will look for either <tt>:subscribers</tt> or
- # <tt>:subscriber</tt> on Subscription, unless a <tt>:source</tt> is given.
- # [:source_type]
- # Specifies type of the source association used by <tt>has_many :through</tt> queries where the source
- # association is a polymorphic +belongs_to+.
- # [:uniq]
- # If true, duplicates will be omitted from the collection. Useful in conjunction with <tt>:through</tt>.
- # [:readonly]
- # If true, all the associated objects are readonly through the association.
- # [:validate]
- # If false, don't validate the associated objects when saving the parent object. true by default.
- # [:autosave]
- # If true, always save any loaded members and destroy members marked for destruction, when saving the parent object. Off by default.
- #
- # Option examples:
- # has_many :comments, :order => "posted_on"
- # has_many :comments, :include => :author
- # has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
- # has_many :tracks, :order => "position", :dependent => :destroy
- # has_many :comments, :dependent => :nullify
- # has_many :tags, :as => :taggable
- # has_many :reports, :readonly => true
- # has_many :subscribers, :through => :subscriptions, :source => :user
- # has_many :subscribers, :class_name => "Person", :finder_sql =>
- # 'SELECT DISTINCT people.* ' +
- # 'FROM people p, post_subscriptions ps ' +
- # 'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' +
- # 'ORDER BY p.first_name'
- def has_many(association_id, options = {}, &extension)
- reflection = create_has_many_reflection(association_id, options, &extension)
- configure_dependency_for_has_many(reflection)
- add_association_callbacks(reflection.name, reflection.options)
-
- if options[:through]
- collection_accessor_methods(reflection, HasManyThroughAssociation)
- else
- collection_accessor_methods(reflection, HasManyAssociation)
- end
- end
-
- # Specifies a one-to-one association with another class. This method should only be used
- # if the other class contains the foreign key. If the current class contains the foreign key,
- # then you should use +belongs_to+ instead. See also ActiveRecord::Associations::ClassMethods's overview
- # on when to use has_one and when to use belongs_to.
- #
- # The following methods for retrieval and query of a single associated object will be added:
- #
- # [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.
- # [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
- # yet been saved. <b>Note:</b> This ONLY works if an association already exists.
- # It will NOT work if the association is +nil+.
- # [create_association(attributes = {})]
- # Returns a new object of the associated type that has been instantiated
- # with +attributes+, linked to this object through a foreign key, and that
- # has already been saved (if it passed the validation).
- #
- # (+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:
- # * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.find(:first, :conditions => "account_id = #{id}")</tt>)
- # * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
- # * <tt>Account#build_beneficiary</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
- # * <tt>Account#create_beneficiary</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
- #
- # === Options
- #
- # The declaration can also include an options hash to specialize the behavior of the association.
- #
- # Options are:
- # [:class_name]
- # Specify the class name of the association. Use it only if that name can't be inferred
- # from the association name. So <tt>has_one :manager</tt> will by default be linked to the Manager class, but
- # if the real class name is Person, you'll have to specify it with this option.
- # [:conditions]
- # Specify the conditions that the associated object must meet in order to be included as a +WHERE+
- # SQL fragment, such as <tt>rank = 5</tt>. Record creation from the association is scoped if a hash
- # is used. <tt>has_one :account, :conditions => {:enabled => true}</tt> will create an enabled account with <tt>@company.create_account</tt>
- # or <tt>@company.build_account</tt>.
- # [:order]
- # Specify the order in which the associated objects are returned as an <tt>ORDER BY</tt> SQL fragment,
- # such as <tt>last_name, first_name DESC</tt>.
- # [:dependent]
- # If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
- # <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method. If set to <tt>:nullify</tt>, the associated
- # object's foreign key is set to +NULL+. Also, association is assigned.
- # [:foreign_key]
- # 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>.
- # [:primary_key]
- # Specify the method that returns the primary key used for the association. By default this is +id+.
- # [:include]
- # Specify second-order associations that should be eager loaded when this object is loaded.
- # [:as]
- # Specifies a polymorphic interface (See <tt>belongs_to</tt>).
- # [:select]
- # By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if, for example, 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.
- # [: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. <tt>has_one :favorite, :through => :favorites</tt> will look for a
- # <tt>:favorite</tt> on Favorite, unless a <tt>:source</tt> is given.
- # [:source_type]
- # Specifies type of the source association used by <tt>has_one :through</tt> queries where the source
- # association is a polymorphic +belongs_to+.
- # [:readonly]
- # If true, the associated object is readonly through the association.
- # [:validate]
- # If false, don't validate the associated object when saving the parent object. +false+ by default.
- # [:autosave]
- # If true, always save the associated object or destroy it if marked for destruction, when saving the parent object. Off by default.
- #
- # Option examples:
- # has_one :credit_card, :dependent => :destroy # destroys the associated credit card
- # has_one :credit_card, :dependent => :nullify # updates the associated records foreign key value to NULL rather than destroying it
- # has_one :last_comment, :class_name => "Comment", :order => "posted_on"
- # has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
- # has_one :attachment, :as => :attachable
- # has_one :boss, :readonly => :true
- # has_one :club, :through => :membership
- # has_one :primary_address, :through => :addressables, :conditions => ["addressable.primary = ?", true], :source => :addressable
- def has_one(association_id, options = {})
- if options[:through]
- reflection = create_has_one_through_reflection(association_id, options)
- association_accessor_methods(reflection, ActiveRecord::Associations::HasOneThroughAssociation)
- else
- reflection = create_has_one_reflection(association_id, options)
- association_accessor_methods(reflection, HasOneAssociation)
- association_constructor_method(:build, reflection, HasOneAssociation)
- association_constructor_method(:create, reflection, HasOneAssociation)
- configure_dependency_for_has_one(reflection)
- end
- end
-
- # Specifies a one-to-one association with another class. This method should only be used
- # if this class contains the foreign key. If the other class contains the foreign key,
- # then you should use +has_one+ instead. See also ActiveRecord::Associations::ClassMethods's overview
- # on when to use +has_one+ and when to use +belongs_to+.
- #
- # Methods will be added for retrieval and query for a single associated object, for which
- # this object holds an id:
- #
- # [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, and sets it as the foreign key.
- # [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 yet been saved.
- # [create_association(attributes = {})]
- # Returns a new object of the associated type that has been instantiated
- # with +attributes+, linked to this object through a foreign key, and that
- # has already been saved (if it passed the validation).
- #
- # (+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:
- # * <tt>Post#author</tt> (similar to <tt>Author.find(author_id)</tt>)
- # * <tt>Post#author=(author)</tt> (similar to <tt>post.author_id = author.id</tt>)
- # * <tt>Post#author?</tt> (similar to <tt>post.author == some_author</tt>)
- # * <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>)
- # The declaration can also include an options hash to specialize the behavior of the association.
- #
- # === Options
- #
- # [:class_name]
- # Specify the class name of the association. Use it only if that name can't be inferred
- # from the association name. So <tt>has_one :author</tt> will by default be linked to the Author class, but
- # if the real class name is Person, you'll have to specify it with this option.
- # [:conditions]
- # Specify the conditions that the associated object must meet in order to be included as a +WHERE+
- # SQL fragment, such as <tt>authorized = 1</tt>.
- # [:select]
- # By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if, for example, 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.
- # [:foreign_key]
- # Specify the foreign key used for the association. By default this is guessed to be the name
- # of the association with an "_id" suffix. So a class that defines a <tt>belongs_to :person</tt> association will use
- # "person_id" as the default <tt>:foreign_key</tt>. Similarly, <tt>belongs_to :favorite_person, :class_name => "Person"</tt>
- # will use a foreign key of "favorite_person_id".
- # [:primary_key]
- # Specify the method that returns the primary key of associated object used for the association. By default this is id.
- # [:dependent]
- # If set to <tt>:destroy</tt>, the associated object is destroyed when this object is. If set to
- # <tt>:delete</tt>, the associated object is deleted *without* calling its destroy method. This option should not be specified when
- # <tt>belongs_to</tt> is used in conjunction with a <tt>has_many</tt> relationship on another class because of the potential to leave
- # orphaned records behind.
- # [:counter_cache]
- # Caches the number of belonging objects on the associate class through the use of +increment_counter+
- # and +decrement_counter+. The counter cache is incremented when an object of this class is created and decremented when it's
- # destroyed. This requires that a column named <tt>#{table_name}_count</tt> (such as +comments_count+ for a belonging Comment class)
- # is used on the associate class (such as a Post class). You can also specify a custom counter cache column by providing
- # a column name instead of a +true+/+false+ value to this option (e.g., <tt>:counter_cache => :my_custom_counter</tt>.)
- # Note: Specifying a counter cache will add it to that model's list of readonly attributes using +attr_readonly+.
- # [:include]
- # Specify second-order associations that should be eager loaded when this object is loaded.
- # [:polymorphic]
- # Specify this association is a polymorphic association by passing +true+.
- # Note: If you've enabled the counter cache, then you may want to add the counter cache attribute
- # to the +attr_readonly+ list in the associated classes (e.g. <tt>class Post; attr_readonly :comments_count; end</tt>).
- # [:readonly]
- # If true, the associated object is readonly through the association.
- # [:validate]
- # If false, don't validate the associated objects when saving the parent object. +false+ by default.
- # [:autosave]
- # If true, always save the associated object or destroy it if marked for destruction, when saving the parent object. Off by default.
- # [:touch]
- # If true, the associated object will be touched (the updated_at/on attributes set to now) when this record is either saved or
- # destroyed. If you specify a symbol, that attribute will be updated with the current time instead of the updated_at/on attribute.
- #
- # 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, :class_name => "Coupon", :foreign_key => "coupon_id",
- # :conditions => 'discounts > #{payments_count}'
- # 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
- def belongs_to(association_id, options = {})
- reflection = create_belongs_to_reflection(association_id, options)
-
- if reflection.options[:polymorphic]
- association_accessor_methods(reflection, BelongsToPolymorphicAssociation)
- else
- association_accessor_methods(reflection, BelongsToAssociation)
- association_constructor_method(:build, reflection, BelongsToAssociation)
- association_constructor_method(:create, reflection, BelongsToAssociation)
- end
-
- add_counter_cache_callbacks(reflection) if options[:counter_cache]
- add_touch_callbacks(reflection, options[:touch]) if options[:touch]
-
- configure_dependency_for_belongs_to(reflection)
- end
-
- # Specifies a many-to-many relationship with another class. This associates two classes via an
- # intermediate join table. Unless the join table is explicitly specified as an option, it is
- # guessed using the lexical order of the class names. So a join between Developer and Project
- # will give the default join table name of "developers_projects" because "D" outranks "P". Note that this precedence
- # is calculated using the <tt><</tt> operator for String. This means that if the strings are of different lengths,
- # and the strings are equal when compared up to the shortest length, then the longer string is considered of higher
- # lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers"
- # to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes",
- # but it in fact generates a join table name of "paper_boxes_papers". Be aware of this caveat, and use the
- # custom <tt>:join_table</tt> option if you need to.
- #
- # The join table should not have a primary key or a model associated with it. You must manually generate the
- # join table with a migration such as this:
- #
- # class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration
- # def self.up
- # create_table :developers_projects, :id => false do |t|
- # t.integer :developer_id
- # t.integer :project_id
- # end
- # end
- #
- # def self.down
- # drop_table :developers_projects
- # end
- # end
- #
- # Deprecated: Any additional fields added to the join table will be placed as attributes when pulling records out through
- # +has_and_belongs_to_many+ associations. Records returned from join tables with additional attributes will be marked as
- # readonly (because we can't save changes to the additional attributes). It's strongly recommended that you upgrade any
- # associations with attributes to a real join model (see introduction).
- #
- # Adds the following methods for retrieval and query:
- #
- # [collection(force_reload = false)]
- # Returns an array of all the associated objects.
- # An empty array is returned if none are found.
- # [collection<<(object, ...)]
- # Adds one or more objects to the collection by creating associations in the join table
- # (<tt>collection.push</tt> and <tt>collection.concat</tt> are aliases to this method).
- # [collection.delete(object, ...)]
- # Removes one or more objects from the collection by removing their associations from the join table.
- # This does not destroy the objects.
- # [collection=objects]
- # Replaces the collection's content by deleting and adding objects as appropriate.
- # [collection_singular_ids]
- # Returns an array of the associated objects' ids.
- # [collection_singular_ids=ids]
- # Replace the collection by the objects identified by the primary keys in +ids+.
- # [collection.clear]
- # Removes every object from the collection. This does not destroy the objects.
- # [collection.empty?]
- # Returns +true+ if there are no associated objects.
- # [collection.size]
- # Returns the number of associated objects.
- # [collection.find(id)]
- # Finds an associated object responding to the +id+ and that
- # meets the condition that it has to be associated with this object.
- # Uses the same rules as ActiveRecord::Base.find.
- # [collection.exists?(...)]
- # Checks whether an associated object with the given conditions exists.
- # Uses the same rules as ActiveRecord::Base.exists?.
- # [collection.build(attributes = {})]
- # Returns a new object of the collection type that has been instantiated
- # with +attributes+ and linked to this object through the join table, but has not yet been saved.
- # [collection.create(attributes = {})]
- # Returns a new object of the collection type that has been instantiated
- # 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:
- # * <tt>Developer#projects</tt>
- # * <tt>Developer#projects<<</tt>
- # * <tt>Developer#projects.delete</tt>
- # * <tt>Developer#projects=</tt>
- # * <tt>Developer#project_ids</tt>
- # * <tt>Developer#project_ids=</tt>
- # * <tt>Developer#projects.clear</tt>
- # * <tt>Developer#projects.empty?</tt>
- # * <tt>Developer#projects.size</tt>
- # * <tt>Developer#projects.find(id)</tt>
- # * <tt>Developer#clients.exists?(...)</tt>
- # * <tt>Developer#projects.build</tt> (similar to <tt>Project.new("project_id" => id)</tt>)
- # * <tt>Developer#projects.create</tt> (similar to <tt>c = Project.new("project_id" => id); c.save; c</tt>)
- # The declaration may include an options hash to specialize the behavior of the association.
- #
- # === Options
- #
- # [:class_name]
- # Specify the class name of the association. Use it only if that name can't be inferred
- # from the association name. So <tt>has_and_belongs_to_many :projects</tt> will by default be linked to the
- # Project class, but if the real class name is SuperProject, you'll have to specify it with this option.
- # [:join_table]
- # Specify the name of the join table if the default based on lexical order isn't what you want.
- # <b>WARNING:</b> If you're overwriting the table name of either class, the +table_name+ method
- # MUST be declared underneath any +has_and_belongs_to_many+ declaration in order to work.
- # [:foreign_key]
- # 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_and_belongs_to_many+ association
- # to Project will use "person_id" as the default <tt>:foreign_key</tt>.
- # [:association_foreign_key]
- # Specify the foreign key used for the association on the receiving side of the association.
- # By default this is guessed to be the name of the associated class in lower-case and "_id" suffixed.
- # So if a Person class makes a +has_and_belongs_to_many+ association to Project,
- # the association will use "project_id" as the default <tt>:association_foreign_key</tt>.
- # [:conditions]
- # Specify the conditions that the associated object must meet in order to be included as a +WHERE+
- # SQL fragment, such as <tt>authorized = 1</tt>. Record creations from the association are scoped if a hash is used.
- # <tt>has_many :posts, :conditions => {:published => true}</tt> will create published posts with <tt>@blog.posts.create</tt>
- # or <tt>@blog.posts.build</tt>.
- # [:order]
- # Specify the order in which the associated objects are returned as an <tt>ORDER BY</tt> SQL fragment,
- # such as <tt>last_name, first_name DESC</tt>
- # [:uniq]
- # If true, duplicate associated objects will be ignored by accessors and query methods.
- # [:finder_sql]
- # Overwrite the default generated SQL statement used to fetch the association with a manual statement
- # [:counter_sql]
- # Specify a complete SQL statement to fetch the size of the association. If <tt>:finder_sql</tt> is
- # specified but not <tt>:counter_sql</tt>, <tt>:counter_sql</tt> will be generated by replacing <tt>SELECT ... FROM</tt> with <tt>SELECT COUNT(*) FROM</tt>.
- # [:delete_sql]
- # Overwrite the default generated SQL statement used to remove links between the associated
- # classes with a manual statement.
- # [:insert_sql]
- # Overwrite the default generated SQL statement used to add links between the associated classes
- # with a manual statement.
- # [:extend]
- # Anonymous module for extending the proxy, see "Association extensions".
- # [:include]
- # Specify second-order associations that should be eager loaded when the collection is loaded.
- # [:group]
- # An attribute name by which the result should be grouped. Uses the <tt>GROUP BY</tt> SQL-clause.
- # [:having]
- # Combined with +:group+ this can be used to filter the records that a <tt>GROUP BY</tt> returns. Uses the <tt>HAVING</tt> SQL-clause.
- # [:limit]
- # An integer determining the limit on the number of rows that should be returned.
- # [:offset]
- # An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
- # [:select]
- # By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if, for example, 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.
- # [:readonly]
- # If true, all the associated objects are readonly through the association.
- # [:validate]
- # If false, don't validate the associated objects when saving the parent object. +true+ by default.
- # [:autosave]
- # If true, always save any loaded members and destroy members marked for destruction, when saving the parent object. Off by default.
- #
- # Option examples:
- # has_and_belongs_to_many :projects
- # has_and_belongs_to_many :projects, :include => [ :milestones, :manager ]
- # has_and_belongs_to_many :nations, :class_name => "Country"
- # has_and_belongs_to_many :categories, :join_table => "prods_cats"
- # has_and_belongs_to_many :categories, :readonly => true
- # has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql =>
- # 'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}'
- def has_and_belongs_to_many(association_id, options = {}, &extension)
- reflection = create_has_and_belongs_to_many_reflection(association_id, options, &extension)
- collection_accessor_methods(reflection, HasAndBelongsToManyAssociation)
-
- # Don't use a before_destroy callback since users' before_destroy
- # callbacks will be executed after the association is wiped out.
- old_method = "destroy_without_habtm_shim_for_#{reflection.name}"
- class_eval <<-end_eval unless method_defined?(old_method)
- alias_method :#{old_method}, :destroy_without_callbacks # alias_method :destroy_without_habtm_shim_for_posts, :destroy_without_callbacks
- def destroy_without_callbacks # def destroy_without_callbacks
- #{reflection.name}.clear # posts.clear
- #{old_method} # destroy_without_habtm_shim_for_posts
- end # end
- end_eval
-
- add_association_callbacks(reflection.name, options)
- end
-
- private
- # Generates a join table name from two provided table names.
- # The names in the join table namesme end up in lexicographic order.
- #
- # join_table_name("members", "clubs") # => "clubs_members"
- # join_table_name("members", "special_clubs") # => "members_special_clubs"
- def join_table_name(first_table_name, second_table_name)
- if first_table_name < second_table_name
- join_table = "#{first_table_name}_#{second_table_name}"
- else
- join_table = "#{second_table_name}_#{first_table_name}"
- end
-
- table_name_prefix + join_table + table_name_suffix
- end
-
- def association_accessor_methods(reflection, association_proxy_class)
- define_method(reflection.name) do |*params|
- force_reload = params.first unless params.empty?
- association = association_instance_get(reflection.name)
-
- if association.nil? || force_reload
- association = association_proxy_class.new(self, reflection)
- retval = association.reload
- if retval.nil? and association_proxy_class == BelongsToAssociation
- association_instance_set(reflection.name, nil)
- return nil
- end
- association_instance_set(reflection.name, association)
- end
-
- association.target.nil? ? nil : association
- end
-
- define_method("loaded_#{reflection.name}?") do
- association = association_instance_get(reflection.name)
- association && association.loaded?
- end
-
- define_method("#{reflection.name}=") do |new_value|
- association = association_instance_get(reflection.name)
-
- if association.nil? || association.target != new_value
- association = association_proxy_class.new(self, reflection)
- end
-
- if association_proxy_class == HasOneThroughAssociation
- association.create_through_record(new_value)
- if new_record?
- association_instance_set(reflection.name, new_value.nil? ? nil : association)
- else
- self.send(reflection.name, new_value)
- end
- else
- association.replace(new_value)
- association_instance_set(reflection.name, new_value.nil? ? nil : association)
- end
- end
-
- define_method("set_#{reflection.name}_target") do |target|
- return if target.nil? and association_proxy_class == BelongsToAssociation
- association = association_proxy_class.new(self, reflection)
- association.target = target
- association_instance_set(reflection.name, association)
- end
- end
-
- def collection_reader_method(reflection, association_proxy_class)
- define_method(reflection.name) do |*params|
- force_reload = params.first unless params.empty?
- association = association_instance_get(reflection.name)
-
- unless association
- association = association_proxy_class.new(self, reflection)
- association_instance_set(reflection.name, association)
- end
-
- association.reload if force_reload
-
- association
- end
-
- define_method("#{reflection.name.to_s.singularize}_ids") do
- if send(reflection.name).loaded? || reflection.options[:finder_sql]
- send(reflection.name).map(&:id)
- else
- send(reflection.name).all(:select => "#{reflection.quoted_table_name}.#{reflection.klass.primary_key}").map(&:id)
- end
- end
- end
-
- def collection_accessor_methods(reflection, association_proxy_class, writer = true)
- collection_reader_method(reflection, association_proxy_class)
-
- if writer
- define_method("#{reflection.name}=") do |new_value|
- # Loads proxy class instance (defined in collection_reader_method) if not already loaded
- association = send(reflection.name)
- association.replace(new_value)
- association
- end
-
- define_method("#{reflection.name.to_s.singularize}_ids=") do |new_value|
- ids = (new_value || []).reject { |nid| nid.blank? }.map(&:to_i)
- send("#{reflection.name}=", reflection.klass.find(ids).index_by(&:id).values_at(*ids))
- end
- end
- end
-
- def association_constructor_method(constructor, reflection, association_proxy_class)
- define_method("#{constructor}_#{reflection.name}") do |*params|
- attributees = params.first unless params.empty?
- replace_existing = params[1].nil? ? true : params[1]
- association = association_instance_get(reflection.name)
-
- unless association
- association = association_proxy_class.new(self, reflection)
- association_instance_set(reflection.name, association)
- end
-
- if association_proxy_class == HasOneAssociation
- association.send(constructor, attributees, replace_existing)
- else
- association.send(constructor, attributees)
- end
- end
- end
-
- def add_counter_cache_callbacks(reflection)
- cache_column = reflection.counter_cache_column
-
- method_name = "belongs_to_counter_cache_after_create_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.class.increment_counter(cache_column, association.id) unless association.nil?
- end
- after_create(method_name)
-
- method_name = "belongs_to_counter_cache_before_destroy_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.class.decrement_counter(cache_column, association.id) unless association.nil?
- end
- before_destroy(method_name)
-
- module_eval(
- "#{reflection.class_name}.send(:attr_readonly,\"#{cache_column}\".intern) if defined?(#{reflection.class_name}) && #{reflection.class_name}.respond_to?(:attr_readonly)"
- )
- end
-
- def add_touch_callbacks(reflection, touch_attribute)
- method_name = "belongs_to_touch_after_save_or_destroy_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
-
- if touch_attribute == true
- association.touch unless association.nil?
- else
- association.touch(touch_attribute) unless association.nil?
- end
- end
- after_save(method_name)
- after_destroy(method_name)
- end
-
- def find_with_associations(options = {})
- catch :invalid_query do
- join_dependency = JoinDependency.new(self, merge_includes(scope(:find, :include), options[:include]), options[:joins])
- rows = select_all_rows(options, join_dependency)
- return join_dependency.instantiate(rows)
- end
- []
- end
-
- # Creates before_destroy callback methods that nullify, delete or destroy
- # has_many associated objects, according to the defined :dependent rule.
- #
- # See HasManyAssociation#delete_records. Dependent associations
- # delete children, otherwise foreign key is set to NULL.
- #
- # The +extra_conditions+ parameter, which is not used within the main
- # Active Record codebase, is meant to allow plugins to define extra
- # finder conditions.
- def configure_dependency_for_has_many(reflection, extra_conditions = nil)
- if reflection.options.include?(:dependent)
- # Add polymorphic type if the :as option is present
- dependent_conditions = []
- dependent_conditions << "#{reflection.primary_key_name} = \#{record.#{reflection.name}.send(:owner_quoted_id)}"
- dependent_conditions << "#{reflection.options[:as]}_type = '#{base_class.name}'" if reflection.options[:as]
- dependent_conditions << sanitize_sql(reflection.options[:conditions], reflection.quoted_table_name) if reflection.options[:conditions]
- dependent_conditions << extra_conditions if extra_conditions
- dependent_conditions = dependent_conditions.collect {|where| "(#{where})" }.join(" AND ")
- dependent_conditions = dependent_conditions.gsub('@', '\@')
- case reflection.options[:dependent]
- when :destroy
- method_name = "has_many_dependent_destroy_for_#{reflection.name}".to_sym
- define_method(method_name) do
- send(reflection.name).each { |o| o.destroy }
- end
- before_destroy method_name
- when :delete_all
- module_eval %Q{
- before_destroy do |record| # before_destroy do |record|
- delete_all_has_many_dependencies(record, # delete_all_has_many_dependencies(record,
- "#{reflection.name}", # "posts",
- #{reflection.class_name}, # Post,
- %@#{dependent_conditions}@) # %@...@) # this is a string literal like %(...)
- end # end
- }
- when :nullify
- module_eval %Q{
- before_destroy do |record| # before_destroy do |record|
- nullify_has_many_dependencies(record, # nullify_has_many_dependencies(record,
- "#{reflection.name}", # "posts",
- #{reflection.class_name}, # Post,
- "#{reflection.primary_key_name}", # "user_id",
- %@#{dependent_conditions}@) # %@...@) # this is a string literal like %(...)
- end # end
- }
- else
- raise ArgumentError, "The :dependent option expects either :destroy, :delete_all, or :nullify (#{reflection.options[:dependent].inspect})"
- end
- end
- end
-
- # Creates before_destroy callback methods that nullify, delete or destroy
- # has_one associated objects, according to the defined :dependent rule.
- def configure_dependency_for_has_one(reflection)
- if reflection.options.include?(:dependent)
- case reflection.options[:dependent]
- when :destroy
- method_name = "has_one_dependent_destroy_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.destroy unless association.nil?
- end
- before_destroy method_name
- when :delete
- method_name = "has_one_dependent_delete_for_#{reflection.name}".to_sym
- define_method(method_name) do
- # Retrieve the associated object and delete it. The retrieval
- # is necessary because there may be multiple associated objects
- # with foreign keys pointing to this object, and we only want
- # to delete the correct one, not all of them.
- association = send(reflection.name)
- association.delete unless association.nil?
- end
- before_destroy method_name
- when :nullify
- method_name = "has_one_dependent_nullify_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.update_attribute(reflection.primary_key_name, nil) unless association.nil?
- end
- before_destroy method_name
- else
- raise ArgumentError, "The :dependent option expects either :destroy, :delete or :nullify (#{reflection.options[:dependent].inspect})"
- end
- end
- end
-
- def configure_dependency_for_belongs_to(reflection)
- if reflection.options.include?(:dependent)
- case reflection.options[:dependent]
- when :destroy
- method_name = "belongs_to_dependent_destroy_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.destroy unless association.nil?
- end
- after_destroy method_name
- when :delete
- method_name = "belongs_to_dependent_delete_for_#{reflection.name}".to_sym
- define_method(method_name) do
- association = send(reflection.name)
- association.delete unless association.nil?
- end
- after_destroy method_name
- else
- raise ArgumentError, "The :dependent option expects either :destroy or :delete (#{reflection.options[:dependent].inspect})"
- end
- end
- end
-
- def delete_all_has_many_dependencies(record, reflection_name, association_class, dependent_conditions)
- association_class.delete_all(dependent_conditions)
- end
-
- def nullify_has_many_dependencies(record, reflection_name, association_class, primary_key_name, dependent_conditions)
- association_class.update_all("#{primary_key_name} = NULL", dependent_conditions)
- end
-
- mattr_accessor :valid_keys_for_has_many_association
- @@valid_keys_for_has_many_association = [
- :class_name, :table_name, :foreign_key, :primary_key,
- :dependent,
- :select, :conditions, :include, :order, :group, :having, :limit, :offset,
- :as, :through, :source, :source_type,
- :uniq,
- :finder_sql, :counter_sql,
- :before_add, :after_add, :before_remove, :after_remove,
- :extend, :readonly,
- :validate
- ]
-
- def create_has_many_reflection(association_id, options, &extension)
- options.assert_valid_keys(valid_keys_for_has_many_association)
- options[:extend] = create_extension_modules(association_id, extension, options[:extend])
-
- create_reflection(:has_many, association_id, options, self)
- end
-
- mattr_accessor :valid_keys_for_has_one_association
- @@valid_keys_for_has_one_association = [
- :class_name, :foreign_key, :remote, :select, :conditions, :order,
- :include, :dependent, :counter_cache, :extend, :as, :readonly,
- :validate, :primary_key
- ]
-
- def create_has_one_reflection(association_id, options)
- options.assert_valid_keys(valid_keys_for_has_one_association)
- create_reflection(:has_one, association_id, options, self)
- end
-
- def create_has_one_through_reflection(association_id, options)
- options.assert_valid_keys(
- :class_name, :foreign_key, :remote, :select, :conditions, :order, :include, :dependent, :counter_cache, :extend, :as, :through, :source, :source_type, :validate
- )
- create_reflection(:has_one, association_id, options, self)
- end
-
- mattr_accessor :valid_keys_for_belongs_to_association
- @@valid_keys_for_belongs_to_association = [
- :class_name, :primary_key, :foreign_key, :foreign_type, :remote, :select, :conditions,
- :include, :dependent, :counter_cache, :extend, :polymorphic, :readonly,
- :validate, :touch
- ]
-
- def create_belongs_to_reflection(association_id, options)
- options.assert_valid_keys(valid_keys_for_belongs_to_association)
- reflection = create_reflection(:belongs_to, association_id, options, self)
-
- if options[:polymorphic]
- reflection.options[:foreign_type] ||= reflection.class_name.underscore + "_type"
- end
-
- reflection
- end
-
- mattr_accessor :valid_keys_for_has_and_belongs_to_many_association
- @@valid_keys_for_has_and_belongs_to_many_association = [
- :class_name, :table_name, :join_table, :foreign_key, :association_foreign_key,
- :select, :conditions, :include, :order, :group, :having, :limit, :offset,
- :uniq,
- :finder_sql, :counter_sql, :delete_sql, :insert_sql,
- :before_add, :after_add, :before_remove, :after_remove,
- :extend, :readonly,
- :validate
- ]
-
- def create_has_and_belongs_to_many_reflection(association_id, options, &extension)
- options.assert_valid_keys(valid_keys_for_has_and_belongs_to_many_association)
-
- options[:extend] = create_extension_modules(association_id, extension, options[:extend])
-
- reflection = create_reflection(:has_and_belongs_to_many, association_id, options, self)
-
- if reflection.association_foreign_key == reflection.primary_key_name
- raise HasAndBelongsToManyAssociationForeignKeyNeeded.new(reflection)
- end
-
- reflection.options[:join_table] ||= join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(reflection.class_name))
-
- reflection
- end
-
- def reflect_on_included_associations(associations)
- [ associations ].flatten.collect { |association| reflect_on_association(association.to_s.intern) }
- end
-
- def guard_against_unlimitable_reflections(reflections, options)
- if (options[:offset] || options[:limit]) && !using_limitable_reflections?(reflections)
- raise(
- ConfigurationError,
- "You can not use offset and limit together with has_many or has_and_belongs_to_many associations"
- )
- end
- end
-
- def select_all_rows(options, join_dependency)
- connection.select_all(
- construct_finder_sql_with_included_associations(options, join_dependency),
- "#{name} Load Including Associations"
- )
- end
-
- def construct_finder_sql_with_included_associations(options, join_dependency)
- scope = scope(:find)
- sql = "SELECT #{column_aliases(join_dependency)} FROM #{(scope && scope[:from]) || options[:from] || quoted_table_name} "
- sql << join_dependency.join_associations.collect{|join| join.association_join }.join
-
- add_joins!(sql, options[:joins], scope)
- add_conditions!(sql, options[:conditions], scope)
- add_limited_ids_condition!(sql, options, join_dependency) if !using_limitable_reflections?(join_dependency.reflections) && ((scope && scope[:limit]) || options[:limit])
-
- add_group!(sql, options[:group], options[:having], scope)
- add_order!(sql, options[:order], scope)
- add_limit!(sql, options, scope) if using_limitable_reflections?(join_dependency.reflections)
- add_lock!(sql, options, scope)
-
- return sanitize_sql(sql)
- end
-
- def add_limited_ids_condition!(sql, options, join_dependency)
- unless (id_list = select_limited_ids_list(options, join_dependency)).empty?
- sql << "#{condition_word(sql)} #{connection.quote_table_name table_name}.#{primary_key} IN (#{id_list}) "
- else
- throw :invalid_query
- end
- end
-
- def select_limited_ids_list(options, join_dependency)
- pk = columns_hash[primary_key]
-
- connection.select_all(
- construct_finder_sql_for_association_limiting(options, join_dependency),
- "#{name} Load IDs For Limited Eager Loading"
- ).collect { |row| connection.quote(row[primary_key], pk) }.join(", ")
- end
-
- def construct_finder_sql_for_association_limiting(options, join_dependency)
- scope = scope(:find)
-
- # Only join tables referenced in order or conditions since this is particularly slow on the pre-query.
- tables_from_conditions = conditions_tables(options)
- tables_from_order = order_tables(options)
- all_tables = tables_from_conditions + tables_from_order
- distinct_join_associations = all_tables.uniq.map{|table|
- join_dependency.joins_for_table_name(table)
- }.flatten.compact.uniq
-
- order = options[:order]
- if scoped_order = (scope && scope[:order])
- order = order ? "#{order}, #{scoped_order}" : scoped_order
- end
-
- is_distinct = !options[:joins].blank? || include_eager_conditions?(options, tables_from_conditions) || include_eager_order?(options, tables_from_order)
- sql = "SELECT "
- if is_distinct
- sql << connection.distinct("#{connection.quote_table_name table_name}.#{primary_key}", order)
- else
- sql << primary_key
- end
- sql << " FROM #{connection.quote_table_name table_name} "
-
- if is_distinct
- sql << distinct_join_associations.collect { |assoc| assoc.association_join }.join
- add_joins!(sql, options[:joins], scope)
- end
-
- add_conditions!(sql, options[:conditions], scope)
- add_group!(sql, options[:group], options[:having], scope)
-
- if order && is_distinct
- connection.add_order_by_for_association_limiting!(sql, :order => order)
- else
- add_order!(sql, options[:order], scope)
- end
-
- add_limit!(sql, options, scope)
-
- return sanitize_sql(sql)
- end
-
- def tables_in_string(string)
- return [] if string.blank?
- string.scan(/([\.a-zA-Z_]+).?\./).flatten
- end
-
- def tables_in_hash(hash)
- return [] if hash.blank?
- tables = hash.map do |key, value|
- if value.is_a?(Hash)
- key.to_s
- else
- tables_in_string(key) if key.is_a?(String)
- end
- end
- tables.flatten.compact
- end
-
- def conditions_tables(options)
- # look in both sets of conditions
- conditions = [scope(:find, :conditions), options[:conditions]].inject([]) do |all, cond|
- case cond
- when nil then all
- when Array then all << tables_in_string(cond.first)
- when Hash then all << tables_in_hash(cond)
- else all << tables_in_string(cond)
- end
- end
- conditions.flatten
- end
-
- def order_tables(options)
- order = [options[:order], scope(:find, :order) ].join(", ")
- return [] unless order && order.is_a?(String)
- tables_in_string(order)
- end
-
- def selects_tables(options)
- select = options[:select]
- return [] unless select && select.is_a?(String)
- tables_in_string(select)
- end
-
- def joined_tables(options)
- scope = scope(:find)
- joins = options[:joins]
- merged_joins = scope && scope[:joins] && joins ? merge_joins(scope[:joins], joins) : (joins || scope && scope[:joins])
- [table_name] + case merged_joins
- when Symbol, Hash, Array
- if array_of_strings?(merged_joins)
- tables_in_string(merged_joins.join(' '))
- else
- join_dependency = ActiveRecord::Associations::ClassMethods::InnerJoinDependency.new(self, merged_joins, nil)
- join_dependency.join_associations.collect {|join_association| [join_association.aliased_join_table_name, join_association.aliased_table_name]}.flatten.compact
- end
- else
- tables_in_string(merged_joins)
- end
- end
-
- # Checks if the conditions reference a table other than the current model table
- def include_eager_conditions?(options, tables = nil, joined_tables = nil)
- ((tables || conditions_tables(options)) - (joined_tables || joined_tables(options))).any?
- end
-
- # Checks if the query order references a table other than the current model's table.
- def include_eager_order?(options, tables = nil, joined_tables = nil)
- ((tables || order_tables(options)) - (joined_tables || joined_tables(options))).any?
- end
-
- def include_eager_select?(options, joined_tables = nil)
- (selects_tables(options) - (joined_tables || joined_tables(options))).any?
- end
-
- def references_eager_loaded_tables?(options)
- joined_tables = joined_tables(options)
- include_eager_order?(options, nil, joined_tables) || include_eager_conditions?(options, nil, joined_tables) || include_eager_select?(options, joined_tables)
- end
-
- def using_limitable_reflections?(reflections)
- reflections.reject { |r| [ :belongs_to, :has_one ].include?(r.macro) }.length.zero?
- end
-
- def column_aliases(join_dependency)
- join_dependency.joins.collect{|join| join.column_names_with_alias.collect{|column_name, aliased_name|
- "#{connection.quote_table_name join.aliased_table_name}.#{connection.quote_column_name column_name} AS #{aliased_name}"}}.flatten.join(", ")
- end
-
- def add_association_callbacks(association_name, options)
- callbacks = %w(before_add after_add before_remove after_remove)
- callbacks.each do |callback_name|
- full_callback_name = "#{callback_name}_for_#{association_name}"
- defined_callbacks = options[callback_name.to_sym]
- if options.has_key?(callback_name.to_sym)
- class_inheritable_reader full_callback_name.to_sym
- write_inheritable_attribute(full_callback_name.to_sym, [defined_callbacks].flatten)
- else
- write_inheritable_attribute(full_callback_name.to_sym, [])
- end
- end
- end
-
- def condition_word(sql)
- sql =~ /where/i ? " AND " : "WHERE "
- end
-
- def create_extension_modules(association_id, block_extension, extensions)
- if block_extension
- extension_module_name = "#{self.to_s.demodulize}#{association_id.to_s.camelize}AssociationExtension"
-
- silence_warnings do
- self.parent.const_set(extension_module_name, Module.new(&block_extension))
- end
- Array(extensions).push("#{self.parent}::#{extension_module_name}".constantize)
- else
- Array(extensions)
- end
- end
-
- class JoinDependency # :nodoc:
- attr_reader :joins, :reflections, :table_aliases
-
- def initialize(base, associations, joins)
- @joins = [JoinBase.new(base, joins)]
- @associations = associations
- @reflections = []
- @base_records_hash = {}
- @base_records_in_order = []
- @table_aliases = Hash.new { |aliases, table| aliases[table] = 0 }
- @table_aliases[base.table_name] = 1
- build(associations)
- end
-
- def join_associations
- @joins[1..-1].to_a
- end
-
- def join_base
- @joins[0]
- end
-
- def instantiate(rows)
- rows.each_with_index do |row, i|
- primary_id = join_base.record_id(row)
- unless @base_records_hash[primary_id]
- @base_records_in_order << (@base_records_hash[primary_id] = join_base.instantiate(row))
- end
- construct(@base_records_hash[primary_id], @associations, join_associations.dup, row)
- end
- remove_duplicate_results!(join_base.active_record, @base_records_in_order, @associations)
- return @base_records_in_order
- end
-
- def remove_duplicate_results!(base, records, associations)
- case associations
- when Symbol, String
- reflection = base.reflections[associations]
- if reflection && [:has_many, :has_and_belongs_to_many].include?(reflection.macro)
- records.each { |record| record.send(reflection.name).target.uniq! }
- end
- when Array
- associations.each do |association|
- remove_duplicate_results!(base, records, association)
- end
- when Hash
- associations.keys.each do |name|
- reflection = base.reflections[name]
- is_collection = [:has_many, :has_and_belongs_to_many].include?(reflection.macro)
-
- parent_records = records.map do |record|
- descendant = record.send(reflection.name)
- next unless descendant
- descendant.target.uniq! if is_collection
- descendant
- end.flatten.compact
-
- remove_duplicate_results!(reflection.klass, parent_records, associations[name]) unless parent_records.empty?
- end
- end
- end
-
- def join_for_table_name(table_name)
- join = (@joins.select{|j|j.aliased_table_name == table_name.gsub(/^\"(.*)\"$/){$1} }.first) rescue nil
- return join unless join.nil?
- @joins.select{|j|j.is_a?(JoinAssociation) && j.aliased_join_table_name == table_name.gsub(/^\"(.*)\"$/){$1} }.first rescue nil
- end
-
- def joins_for_table_name(table_name)
- join = join_for_table_name(table_name)
- result = nil
- if join && join.is_a?(JoinAssociation)
- result = [join]
- if join.parent && join.parent.is_a?(JoinAssociation)
- result = joins_for_table_name(join.parent.aliased_table_name) +
- result
- end
- end
- result
- end
-
- protected
- def build(associations, parent = nil)
- parent ||= @joins.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?"
- @reflections << reflection
- @joins << build_join_association(reflection, parent)
- when Array
- associations.each do |association|
- build(association, parent)
- end
- when Hash
- associations.keys.sort{|a,b|a.to_s<=>b.to_s}.each do |name|
- build(name, parent)
- build(associations[name])
- end
- else
- raise ConfigurationError, associations.inspect
- end
- end
-
- # overridden in InnerJoinDependency subclass
- def build_join_association(reflection, parent)
- JoinAssociation.new(reflection, self, parent)
- end
-
- def construct(parent, associations, joins, row)
- case associations
- when Symbol, String
- join = joins.detect{|j| j.reflection.name.to_s == associations.to_s && j.parent_table_name == parent.class.table_name }
- raise(ConfigurationError, "No such association") if join.nil?
-
- joins.delete(join)
- construct_association(parent, join, row)
- when Array
- associations.each do |association|
- construct(parent, association, joins, row)
- end
- when Hash
- associations.keys.sort{|a,b|a.to_s<=>b.to_s}.each do |name|
- join = joins.detect{|j| j.reflection.name.to_s == name.to_s && j.parent_table_name == parent.class.table_name }
- raise(ConfigurationError, "No such association") if join.nil?
-
- association = construct_association(parent, join, row)
- joins.delete(join)
- construct(association, associations[name], joins, row) if association
- end
- else
- raise ConfigurationError, associations.inspect
- end
- end
-
- def construct_association(record, join, row)
- case join.reflection.macro
- when :has_many, :has_and_belongs_to_many
- collection = record.send(join.reflection.name)
- collection.loaded
-
- return nil if record.id.to_s != join.parent.record_id(row).to_s or row[join.aliased_primary_key].nil?
- association = join.instantiate(row)
- collection.target.push(association)
- when :has_one
- return if record.id.to_s != join.parent.record_id(row).to_s
- return if record.instance_variable_defined?("@#{join.reflection.name}")
- association = join.instantiate(row) unless row[join.aliased_primary_key].nil?
- record.send("set_#{join.reflection.name}_target", association)
- when :belongs_to
- return if record.id.to_s != join.parent.record_id(row).to_s or row[join.aliased_primary_key].nil?
- association = join.instantiate(row)
- record.send("set_#{join.reflection.name}_target", association)
- else
- raise ConfigurationError, "unknown macro: #{join.reflection.macro}"
- end
- return association
- end
-
- class JoinBase # :nodoc:
- attr_reader :active_record, :table_joins
- delegate :table_name, :column_names, :primary_key, :reflections, :sanitize_sql, :to => :active_record
-
- def initialize(active_record, joins = nil)
- @active_record = active_record
- @cached_record = {}
- @table_joins = joins
- end
-
- def aliased_prefix
- "t0"
- end
-
- def aliased_primary_key
- "#{aliased_prefix}_r0"
- end
-
- def aliased_table_name
- active_record.table_name
- end
-
- def column_names_with_alias
- unless defined?(@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)
- column_names_with_alias.inject({}){|record, (cn, an)| record[cn] = row[an]; record}
- 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
-
- class JoinAssociation < JoinBase # :nodoc:
- attr_reader :reflection, :parent, :aliased_table_name, :aliased_prefix, :aliased_join_table_name, :parent_table_name
- delegate :options, :klass, :through_reflection, :source_reflection, :to => :reflection
-
- def initialize(reflection, join_dependency, parent = nil)
- reflection.check_validity!
- if reflection.options[:polymorphic]
- raise EagerLoadPolymorphicError.new(reflection)
- end
-
- super(reflection.klass)
- @join_dependency = join_dependency
- @parent = parent
- @reflection = reflection
- @aliased_prefix = "t#{ join_dependency.joins.size }"
- @parent_table_name = parent.active_record.table_name
- @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")
- end
-
- if [: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 association_join
- connection = reflection.active_record.connection
- join = case reflection.macro
- when :has_and_belongs_to_many
- " #{join_type} %s ON %s.%s = %s.%s " % [
- table_alias_for(options[:join_table], aliased_join_table_name),
- connection.quote_table_name(aliased_join_table_name),
- options[:foreign_key] || reflection.active_record.to_s.foreign_key,
- connection.quote_table_name(parent.aliased_table_name),
- reflection.active_record.primary_key] +
- " #{join_type} %s ON %s.%s = %s.%s " % [
- table_name_and_alias,
- connection.quote_table_name(aliased_table_name),
- klass.primary_key,
- connection.quote_table_name(aliased_join_table_name),
- options[:association_foreign_key] || klass.to_s.foreign_key
- ]
- when :has_many, :has_one
- case
- when reflection.options[:through]
- through_conditions = through_reflection.options[:conditions] ? "AND #{interpolate_sql(sanitize_sql(through_reflection.options[:conditions]))}" : ''
-
- jt_foreign_key = jt_as_extra = jt_source_extra = jt_sti_extra = nil
- first_key = second_key = as_extra = nil
-
- if through_reflection.options[:as] # has_many :through against a polymorphic join
- jt_foreign_key = through_reflection.options[:as].to_s + '_id'
- jt_as_extra = " AND %s.%s = %s" % [
- connection.quote_table_name(aliased_join_table_name),
- connection.quote_column_name(through_reflection.options[:as].to_s + '_type'),
- klass.quote_value(parent.active_record.base_class.name)
- ]
- else
- jt_foreign_key = through_reflection.primary_key_name
- end
-
- case source_reflection.macro
- when :has_many
- if source_reflection.options[:as]
- first_key = "#{source_reflection.options[:as]}_id"
- second_key = options[:foreign_key] || primary_key
- as_extra = " AND %s.%s = %s" % [
- connection.quote_table_name(aliased_table_name),
- connection.quote_column_name("#{source_reflection.options[:as]}_type"),
- klass.quote_value(source_reflection.active_record.base_class.name)
- ]
- else
- first_key = through_reflection.klass.base_class.to_s.foreign_key
- second_key = options[:foreign_key] || primary_key
- end
-
- unless through_reflection.klass.descends_from_active_record?
- jt_sti_extra = " AND %s.%s = %s" % [
- connection.quote_table_name(aliased_join_table_name),
- connection.quote_column_name(through_reflection.active_record.inheritance_column),
- through_reflection.klass.quote_value(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_source_extra = " AND %s.%s = %s" % [
- connection.quote_table_name(aliased_join_table_name),
- connection.quote_column_name(reflection.source_reflection.options[:foreign_type]),
- klass.quote_value(reflection.options[:source_type])
- ]
- else
- second_key = source_reflection.primary_key_name
- end
- end
-
- " #{join_type} %s ON (%s.%s = %s.%s%s%s%s) " % [
- table_alias_for(through_reflection.klass.table_name, aliased_join_table_name),
- connection.quote_table_name(parent.aliased_table_name),
- connection.quote_column_name(parent.primary_key),
- connection.quote_table_name(aliased_join_table_name),
- connection.quote_column_name(jt_foreign_key),
- jt_as_extra, jt_source_extra, jt_sti_extra
- ] +
- " #{join_type} %s ON (%s.%s = %s.%s%s) " % [
- table_name_and_alias,
- connection.quote_table_name(aliased_table_name),
- connection.quote_column_name(first_key),
- connection.quote_table_name(aliased_join_table_name),
- connection.quote_column_name(second_key),
- as_extra
- ]
-
- when reflection.options[:as] && [:has_many, :has_one].include?(reflection.macro)
- " #{join_type} %s ON %s.%s = %s.%s AND %s.%s = %s" % [
- table_name_and_alias,
- connection.quote_table_name(aliased_table_name),
- "#{reflection.options[:as]}_id",
- connection.quote_table_name(parent.aliased_table_name),
- parent.primary_key,
- connection.quote_table_name(aliased_table_name),
- "#{reflection.options[:as]}_type",
- klass.quote_value(parent.active_record.base_class.name)
- ]
- else
- foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key
- " #{join_type} %s ON %s.%s = %s.%s " % [
- table_name_and_alias,
- aliased_table_name,
- foreign_key,
- parent.aliased_table_name,
- reflection.options[:primary_key] || parent.primary_key
- ]
- end
- when :belongs_to
- " #{join_type} %s ON %s.%s = %s.%s " % [
- table_name_and_alias,
- connection.quote_table_name(aliased_table_name),
- reflection.klass.primary_key,
- connection.quote_table_name(parent.aliased_table_name),
- options[:foreign_key] || reflection.primary_key_name
- ]
- else
- ""
- end || ''
- join << %(AND %s) % [
- klass.send(:type_condition, aliased_table_name)] unless klass.descends_from_active_record?
-
- [through_reflection, reflection].each do |ref|
- join << "AND #{interpolate_sql(sanitize_sql(ref.options[:conditions], aliased_table_name))} " if ref && ref.options[:conditions]
- end
-
- join
- end
-
- protected
-
- def aliased_table_name_for(name, suffix = nil)
- if !parent.table_joins.blank? && parent.table_joins.to_s.downcase =~ %r{join(\s+\w+)?\s+#{active_record.connection.quote_table_name name.downcase}\son}
- @join_dependency.table_aliases[name] += 1
- end
-
- unless @join_dependency.table_aliases[name].zero?
- # if the table name has been used, then use an alias
- name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}"
- table_index = @join_dependency.table_aliases[name]
- @join_dependency.table_aliases[name] += 1
- name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index+1}" if table_index > 0
- else
- @join_dependency.table_aliases[name] += 1
- end
-
- name
- end
-
- def pluralize(table_name)
- ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name
- end
-
- def table_alias_for(table_name, table_alias)
- "#{reflection.active_record.connection.quote_table_name(table_name)} #{table_alias if table_name != table_alias}".strip
- end
-
- def table_name_and_alias
- table_alias_for table_name, @aliased_table_name
- end
-
- def interpolate_sql(sql)
- instance_eval("%@#{sql.gsub('@', '\@')}@")
- end
-
- private
- def join_type
- "LEFT OUTER JOIN"
- end
- end
- end
-
- class InnerJoinDependency < JoinDependency # :nodoc:
- protected
- def build_join_association(reflection, parent)
- InnerJoinAssociation.new(reflection, self, parent)
- end
-
- class InnerJoinAssociation < JoinAssociation
- private
- def join_type
- "INNER JOIN"
- end
- end
- end
-
- end
- end
-end
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