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rails--rails/activerecord/lib/active_record/associations.rb
David Heinemeier Hansson 823554eafe Added support for associating unsaved objects #402 [Tim Bates] 
Added replace to associations, so you can do project.manager.replace(new_manager) or project.milestones.replace(new_milestones) #402 [Tim Bates]
Added build and create methods to has_one and belongs_to associations, so you can now do project.manager.build(attributes) #402 [Tim Bates]
Fixed that Base#== wouldn't work for multiple references to the same unsaved object #402 [Tim Bates]
Added that if a before_* callback returns false, all the later callbacks and the associated action are cancelled. If an after_* callback returns false, all the later callbacks are cancelled. Callbacks are generally run in the order they are defined, with the exception of callbacks defined as methods on the model, which are called last. #402 [Tim Bates]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@417 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
2005-01-15 17:45:16 +00:00

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require 'active_record/associations/association_proxy'
require 'active_record/associations/association_collection'
require 'active_record/associations/belongs_to_association'
require 'active_record/associations/has_one_association'
require 'active_record/associations/has_many_association'
require 'active_record/associations/has_and_belongs_to_many_association'
require 'active_record/deprecated_associations'
module ActiveRecord
module Associations # :nodoc:
def self.append_features(base)
super
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
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 was as Ruby's own attr*
# 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#project_manager.build, Project#project_manager.create</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(conditions),</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>
#
# == Example
#
# link:../examples/associations.png
#
# == Is it belongs_to or has_one?
#
# Both express a 1-1 relationship, the difference is mostly where to place the foreign key, which goes on the table for the class
# saying belongs_to. Example:
#
# class Post < ActiveRecord::Base
# has_one :author
# end
#
# class Author < ActiveRecord::Base
# belongs_to :post
# end
#
# The tables for these classes could look something like:
#
# CREATE TABLE posts (
# id int(11) NOT NULL auto_increment,
# title varchar default NULL,
# PRIMARY KEY (id)
# )
#
# CREATE TABLE authors (
# id int(11) NOT NULL auto_increment,
# post_id int(11) default NULL,
# 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 behaviour you should be
# aware of, mostly involving the saving of associated objects.
#
# === 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 (new_record? == true).
# * 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 #association.build 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 #push or similar) fails, then #push returns false.
# * You can add an object to a collection without automatically saving it by using the #collection.build method (documented below).
# * All unsaved (new_record? == true) members of the collection are automatically saved when the parent is saved.
#
# == 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
#
# == 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 Company < ActiveRecord::Base; end
# end
# end
#
# When Firm#clients is called, it'll in turn call <tt>MyApplication::Business::Company.find(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, such as:
#
# 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 ActiveRecord::AssociationTypeMismatch
#
# 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 a ActiveRecord::AssociationTypeMismatch.
#
# == Options
#
# All of the association macros can be specialized through options which makes more complex cases than the simple and guessable ones
# possible.
module ClassMethods
# Adds the following methods for retrieval and query of collections of associated objects.
# +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>.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none are found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by setting their foreign keys to the collection's primary key.
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by setting their foreign keys to NULL. This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
# * <tt>collection.find(id)</tt> - finds an associated object responding to the +id+ and that
# meets the condition that it has to be associated with this object.
# * <tt>collection.find_all(conditions = nil, orderings = nil, limit = nil, joins = nil)</tt> - finds all associated objects responding
# criterias mentioned (like in the standard find_all) and that meets the condition that it has to be associated with this object.
# * <tt>collection.build(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key but has not yet been saved.
# * <tt>collection.create(attributes = {})</tt> - returns a new object of the collection type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: A Firm class declares <tt>has_many :clients</tt>, which will add:
# * <tt>Firm#clients</tt> (similar to <tt>Clients.find_all "firm_id = #{id}"</tt>)
# * <tt>Firm#clients<<</tt>
# * <tt>Firm#clients.delete</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_on_conditions(id, "firm_id = #{id}")</tt>)
# * <tt>Firm#clients.find_all</tt> (similar to <tt>Client.find_all "firm_id = #{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("client_id" => id); c.save; c</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# 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.
# * <tt>:conditions</tt> - specify the conditions that the associated objects must meet in order to be included as a "WHERE"
# sql fragment, such as "price > 5 AND name LIKE 'B%'".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment,
# such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - 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 foreign_key.
# * <tt>:dependent</tt> - if set to true all the associated object are destroyed alongside this object.
# May not be set if :exclusively_dependent is also set.
# * <tt>:exclusively_dependent</tt> - if set to true all the associated object are deleted in one SQL statement without having their
# before_destroy callback run. This should only be used on associations that depend solely on this class and don't need to do any
# clean-up in before_destroy. The upside is that it's much faster, especially if there's a counter_cache involved.
# May not be set if :dependent is also set.
# * <tt>:finder_sql</tt> - specify a complete SQL statement to fetch the association. This is a good way to go for complex
# associations that depends on multiple tables. Note: When this option is used, +find_in_collection+ is _not_ added.
# * <tt>:counter_sql</tt> - specify a complete SQL statement to fetch the size of the association. If +:finder_sql+ is
# specified but +:counter_sql+, +:counter_sql+ will be generated by replacing SELECT ... FROM with SELECT COUNT(*) FROM.
#
# Option examples:
# has_many :comments, :order => "posted_on"
# has_many :people, :class_name => "Person", :conditions => "deleted = 0", :order => "name"
# has_many :tracks, :order => "position", :dependent => true
# 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 = {})
validate_options([ :foreign_key, :class_name, :exclusively_dependent, :dependent, :conditions, :order, :finder_sql, :counter_sql ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
if options[:dependent] and options[:exclusively_dependent]
raise ArgumentError, ':dependent and :exclusively_dependent are mutually exclusive options. You may specify one or the other.' # ' ruby-mode
elsif options[:dependent]
module_eval "before_destroy '#{association_name}.each { |o| o.destroy }'"
elsif options[:exclusively_dependent]
module_eval "before_destroy { |record| #{association_class_name}.delete_all(%(#{association_class_primary_key_name} = \#{record.quoted_id})) }"
end
add_multiple_associated_save_callbacks(association_name)
association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasManyAssociation)
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
deprecated_find_in_collection_method(association_name)
deprecated_find_all_in_collection_method(association_name)
deprecated_collection_create_method(association_name)
deprecated_collection_build_method(association_name)
end
# Adds the following methods for retrieval and query of a single associated object.
# +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>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, sets it as the foreign key,
# and saves the associate object.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
# * <tt>association.build(attributes = {})</tt> - 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.
# * <tt>association.create(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: An Account class declares <tt>has_one :beneficiary</tt>, which will add:
# * <tt>Account#beneficiary</tt> (similar to <tt>Beneficiary.find_first "account_id = #{id}"</tt>)
# * <tt>Account#beneficiary=(beneficiary)</tt> (similar to <tt>beneficiary.account_id = account.id; beneficiary.save</tt>)
# * <tt>Account#beneficiary.nil?</tt>
# * <tt>Account#beneficiary.build</tt> (similar to <tt>Beneficiary.new("account_id" => id)</tt>)
# * <tt>Account#beneficiary.create</tt> (similar to <tt>b = Beneficiary.new("account_id" => id); b.save; b</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# 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.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "rank = 5".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:dependent</tt> - if set to true the associated object is destroyed alongside this object
# * <tt>:foreign_key</tt> - 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 foreign_key.
#
# Option examples:
# has_one :credit_card, :dependent => true
# has_one :last_comment, :class_name => "Comment", :order => "posted_on"
# has_one :project_manager, :class_name => "Person", :conditions => "role = 'project_manager'"
def has_one(association_id, options = {})
validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
module_eval do
after_save <<-EOF
association = instance_variable_get("@#{association_name}")
if (true or @new_record_before_save) and association.respond_to?(:loaded?) and not association.nil?
association["#{association_class_primary_key_name}"] = id
association.save(true)
association.send(:construct_sql)
end
EOF
end
association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasOneAssociation)
module_eval "before_destroy '#{association_name}.destroy unless #{association_name}.nil?'" if options[:dependent]
# deprecated api
deprecated_has_association_method(association_name)
deprecated_build_method("build_", association_name, association_class_name, association_class_primary_key_name)
deprecated_create_method("create_", association_name, association_class_name, association_class_primary_key_name)
deprecated_association_comparison_method(association_name, association_class_name)
end
# Adds the following methods for retrieval and query for a single associated object that this object holds an id to.
# +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>.
# * <tt>association(force_reload = false)</tt> - returns the associated object. Nil is returned if none is found.
# * <tt>association=(associate)</tt> - assigns the associate object, extracts the primary key, and sets it as the foreign key.
# * <tt>association.nil?</tt> - returns true if there is no associated object.
# * <tt>association.build(attributes = {})</tt> - 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.
# * <tt>association.create(attributes = {})</tt> - returns a new object of the associated type that has been instantiated
# with +attributes+ and linked to this object through a foreign key and that has already been saved (if it passed the validation).
#
# Example: A Post class declares <tt>has_one :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#author.nil?</tt>
# * <tt>Post#author.build</tt> (similar to <tt>Author.new("post_id" => id)</tt>)
# * <tt>Post#author.create</tt> (similar to <tt>b = Author.new("post_id" => id); b.save; b</tt>)
# The declaration can also include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# 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.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order from which the associated object will be picked at the top. Specified as
# an "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:foreign_key</tt> - specify the foreign key used for the association. By default this is guessed to be the name
# of the associated class in lower-case and "_id" suffixed. So a +Person+ class that makes a belongs_to association to a
# +Boss+ class will use "boss_id" as the default foreign_key.
# * <tt>:counter_cache</tt> - caches the number of belonging objects on the associate class through 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 "#{table_name}_count" (such as comments_count for a belonging Comment class)
# is used on the associate class (such as a Post class).
#
# Option examples:
# belongs_to :firm, :foreign_key => "client_of"
# 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}'
def belongs_to(association_id, options = {})
validate_options([ :class_name, :foreign_key, :remote, :conditions, :order, :dependent, :counter_cache ], options.keys)
association_name, association_class_name, class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key], false)
require_association_class(association_class_name)
association_class_primary_key_name = options[:foreign_key] || Inflector.underscore(Inflector.demodulize(association_class_name)) + "_id"
association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, BelongsToAssociation)
module_eval do
before_save <<-EOF
association = instance_variable_get("@#{association_name}")
if association.respond_to?(:loaded?) and not association.nil? and association.new_record?
association.save(true)
self["#{association_class_primary_key_name}"] = association.id
association.send(:construct_sql)
end
EOF
end
if options[:counter_cache]
module_eval(
"after_create '#{association_class_name}.increment_counter(\"#{Inflector.pluralize(self.to_s.downcase). + "_count"}\", #{association_class_primary_key_name})" +
" unless #{association_name}.nil?'"
)
module_eval(
"before_destroy '#{association_class_name}.decrement_counter(\"#{Inflector.pluralize(self.to_s.downcase) + "_count"}\", #{association_class_primary_key_name})" +
" unless #{association_name}.nil?'"
)
end
# deprecated api
deprecated_has_association_method(association_name)
deprecated_association_comparison_method(association_name, association_class_name)
end
# 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".
#
# Any additional fields added to the join table will be placed as attributes when pulling records out through
# has_and_belongs_to_many associations. This is helpful when have information about the association itself
# that you want available on retrieval. Note that any fields in the join table will override matching field names
# in the two joined tables. As a consequence, having an "id" field in the join table usually has the undesirable
# result of clobbering the "id" fields in either of the other two tables.
#
#
# Adds the following methods for retrieval and query.
# +collection+ is replaced with the symbol passed as the first argument, so
# <tt>has_and_belongs_to_many :categories</tt> would add among others +categories.empty?+.
# * <tt>collection(force_reload = false)</tt> - returns an array of all the associated objects.
# An empty array is returned if none is found.
# * <tt>collection<<(object, ...)</tt> - adds one or more objects to the collection by creating associations in the join table
# (collection.push and collection.concat are aliases to this method).
# * <tt>collection.push_with_attributes(object, join_attributes)</tt> - adds one to the collection by creating an association in the join table that
# also holds the attributes from <tt>join_attributes</tt> (should be a hash with the column names as keys). This can be used to have additional
# attributes on the join, which will be injected into the associated objects when they are retrieved through the collection.
# (collection.concat_with_attributes is an alias to this method).
# * <tt>collection.delete(object, ...)</tt> - removes one or more objects from the collection by removing their associations from the join table.
# This does not destroy the objects.
# * <tt>collection.clear</tt> - removes every object from the collection. This does not destroy the objects.
# * <tt>collection.empty?</tt> - returns true if there are no associated objects.
# * <tt>collection.size</tt> - returns the number of associated objects.
# * <tt>collection.find(id)</tt> - finds an associated object responding to the +id+ and that
# meets the condition that it has to be associated with this object.
#
# Example: An 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.push_with_attributes</tt>
# * <tt>Developer#projects.delete</tt>
# * <tt>Developer#projects.clear</tt>
# * <tt>Developer#projects.empty?</tt>
# * <tt>Developer#projects.size</tt>
# * <tt>Developer#projects.find(id)</tt>
# The declaration may include an options hash to specialize the behavior of the association.
#
# Options are:
# * <tt>:class_name</tt> - specify the class name of the association. Use it only if that name can't be infered
# 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.
# * <tt>:join_table</tt> - specify the name of the join table if the default based on lexical order isn't what you want.
# WARNING: 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.
# * <tt>:foreign_key</tt> - 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
# will use "person_id" as the default foreign_key.
# * <tt>:association_foreign_key</tt> - specify the association foreign key used for the association. By default this is
# guessed to be the name of the associated class in lower-case and "_id" suffixed. So the associated class is +Project+
# that makes a has_and_belongs_to_many association will use "project_id" as the default association foreign_key.
# * <tt>:conditions</tt> - specify the conditions that the associated object must meet in order to be included as a "WHERE"
# sql fragment, such as "authorized = 1".
# * <tt>:order</tt> - specify the order in which the associated objects are returned as a "ORDER BY" sql fragment, such as "last_name, first_name DESC"
# * <tt>:uniq</tt> - if set to true, duplicate associated objects will be ignored by accessors and query methods
# * <tt>:finder_sql</tt> - overwrite the default generated SQL used to fetch the association with a manual one
# * <tt>:delete_sql</tt> - overwrite the default generated SQL used to remove links between the associated
# classes with a manual one
# * <tt>:insert_sql</tt> - overwrite the default generated SQL used to add links between the associated classes
# with a manual one
#
# Option examples:
# has_and_belongs_to_many :projects
# has_and_belongs_to_many :nations, :class_name => "Country"
# has_and_belongs_to_many :categories, :join_table => "prods_cats"
def has_and_belongs_to_many(association_id, options = {})
validate_options([ :class_name, :table_name, :foreign_key, :association_foreign_key, :conditions,
:join_table, :finder_sql, :delete_sql, :insert_sql, :order, :uniq ], options.keys)
association_name, association_class_name, association_class_primary_key_name =
associate_identification(association_id, options[:class_name], options[:foreign_key])
require_association_class(association_class_name)
options[:join_table] ||= join_table_name(undecorated_table_name(self.to_s), undecorated_table_name(association_class_name))
add_multiple_associated_save_callbacks(association_name)
association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, HasAndBelongsToManyAssociation)
before_destroy_sql = "DELETE FROM #{options[:join_table]} WHERE #{association_class_primary_key_name} = \\\#{self.quoted_id}"
module_eval(%{before_destroy "self.connection.delete(%{#{before_destroy_sql}})"}) # "
# deprecated api
deprecated_collection_count_method(association_name)
deprecated_add_association_relation(association_name)
deprecated_remove_association_relation(association_name)
deprecated_has_collection_method(association_name)
end
private
# Raises an exception if an invalid option has been specified to prevent misspellings from slipping through
def validate_options(valid_option_keys, supplied_option_keys)
unknown_option_keys = supplied_option_keys - valid_option_keys
raise(ActiveRecord::ActiveRecordError, "Unknown options: #{unknown_option_keys}") unless unknown_option_keys.empty?
end
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 associate_identification(association_id, association_class_name, foreign_key, plural = true)
if association_class_name !~ /::/
association_class_name = type_name_with_module(
association_class_name ||
Inflector.camelize(plural ? Inflector.singularize(association_id.id2name) : association_id.id2name)
)
end
primary_key_name = foreign_key || Inflector.underscore(Inflector.demodulize(name)) + "_id"
return association_id.id2name, association_class_name, primary_key_name
end
def association_accessor_methods(association_name, association_class_name, association_class_primary_key_name, options, association_proxy_class)
define_method(association_name) do |*params|
force_reload = params.first unless params.empty?
association = instance_variable_get("@#{association_name}")
unless association.respond_to?(:loaded?)
association = association_proxy_class.new(self,
association_name, association_class_name,
association_class_primary_key_name, options)
instance_variable_set("@#{association_name}", association)
end
association.reload if force_reload
association
end
define_method("#{association_name}=") do |new_value|
association = instance_variable_get("@#{association_name}")
unless association.respond_to?(:loaded?)
association = association_proxy_class.new(self,
association_name, association_class_name,
association_class_primary_key_name, options)
instance_variable_set("@#{association_name}", association)
end
association.replace(new_value)
association
end
end
def require_association_class(class_name)
require_association(Inflector.underscore(class_name)) if class_name
end
def add_multiple_associated_save_callbacks(association_name)
module_eval do
before_save <<-end_eval
@new_record_before_save = new_record?
association = instance_variable_get("@#{association_name}")
if association.respond_to?(:loaded?)
if new_record?
records_to_save = association
else
records_to_save = association.select{ |record| record.new_record? }
end
records_to_save.inject(true) do |result,record|
result &&= record.valid?
end
end
end_eval
end
module_eval do
after_save <<-end_eval
association = instance_variable_get("@#{association_name}")
if association.respond_to?(:loaded?)
if @new_record_before_save
records_to_save = association
else
records_to_save = association.select{ |record| record.new_record? }
end
records_to_save.each{ |record| association.send(:insert_record, record) }
association.send(:construct_sql) # reconstruct the SQL queries now that we know the owner's id
end
end_eval
end
end
end
end
end
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