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Change has_many :through to use the :source option to specify the sou…

…rce association. :class_name is now ignored. [Rick Olson]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4022 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
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commit 38bae0a9695aeaf200b5d62cee2dba2928c847d9 1 parent cb069ea
@technoweenie technoweenie authored
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13 activerecord/CHANGELOG
@@ -1,5 +1,18 @@
*SVN*
+* Change has_many :through to use the :source option to specify the source association. :class_name is now ignored. [Rick Olson]
+
+ class Connection < ActiveRecord::Base
+ belongs_to :user
+ belongs_to :channel
+ end
+
+ class Channel < ActiveRecord::Base
+ has_many :connections
+ has_many :contacts, :through => :connections, :class_name => 'User' # OLD
+ has_many :contacts, :through => :connections, :source => :user # NEW
+ end
+
* Fixed DB2 adapter so nullable columns will be determines correctly now and quotes from column default values will be removed #4350 [contact@maik-schmidt.de]
* Allow overriding of find parameters in scoped has_many :through calls [Rick Olson]
View
70 activerecord/lib/active_record/associations.rb
@@ -15,7 +15,7 @@ def initialize(reflection)
end
def message
- "Could not find the association '#{@reflection.options[:through]}' in model #{@reflection.klass}"
+ "Could not find the association #{@reflection.options[:through].inspect} in model #{@reflection.klass}"
end
end
@@ -32,13 +32,15 @@ def message
end
class HasManyThroughSourceAssociationNotFoundError < ActiveRecordError
- def initialize(through_reflection, source_reflection_names)
- @through_reflection = through_reflection
- @source_reflection_names = source_reflection_names
+ def initialize(reflection)
+ @reflection = 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 }
end
def message
- "Could not find the source associations #{@source_reflection_names.to_sentence} in model #{@through_reflection.klass}"
+ "Could not find the source association(s) #{@source_reflection_names.collect(&:inspect).to_sentence :connector => 'or'} 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 :connector => 'or'}?"
end
end
@@ -48,7 +50,7 @@ def initialize(reflection)
end
def message
- "Can not eagerly load the polymorphic association '#{@reflection.name}'"
+ "Can not eagerly load the polymorphic association #{@reflection.name.inspect}"
end
end
@@ -201,6 +203,46 @@ def clear_association_cache #:nodoc:
# has_many :people, :extend => FindOrCreateByNameExtension
# end
#
+ # == Association Join Models
+ #
+ # Has Many associations can be configured with the :through option to use an explicit join model to retrieve the data. This
+ # operates similarly to a <tt>has_and_belongs_to_many</tt> 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.
+ #
# == Caching
#
# All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically
@@ -263,7 +305,7 @@ def clear_association_cache #:nodoc:
#
# It's currently not possible to use eager loading on multiple associations from the same table. Eager loading will not pull
# additional attributes on join tables, so "rich associations" with has_and_belongs_to_many is not a good fit for eager loading.
- #
+ #
# == Table Aliasing
#
# ActiveRecord uses table aliasing in the case that a table is referenced multiple times in a join. If a table is referenced only once,
@@ -423,6 +465,12 @@ module ClassMethods
# * <tt>:offset</tt>: An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
# * <tt>:select</tt>: By default, this is * as in SELECT * FROM, but can be changed if you for example want to do a join, but not
# include the joined columns.
+ # * <tt>:through</tt>: Specifies a Join Model to perform the query through. 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>
+ # or <tt>has_many</tt> association.
+ # * <tt>:source</tt>: 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 +:subscribers+ or
+ # +:subscriber+ on +Subscription+, unless a +:source+ is given.
#
# Option examples:
# has_many :comments, :order => "posted_on"
@@ -430,11 +478,15 @@ module ClassMethods
# 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 :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'
+ #
+ # Specifying the :through option
+ #
def has_many(association_id, options = {}, &extension)
reflection = create_has_many_reflection(association_id, options, &extension)
@@ -953,7 +1005,7 @@ def create_has_many_reflection(association_id, options, &extension)
:class_name, :table_name, :foreign_key,
:exclusively_dependent, :dependent,
:select, :conditions, :include, :order, :group, :limit, :offset,
- :as, :through,
+ :as, :through, :source,
:finder_sql, :counter_sql,
:before_add, :after_add, :before_remove, :after_remove,
:extend
@@ -1320,7 +1372,7 @@ def initialize(reflection, join_dependency, parent = nil)
end
if reflection.macro == :has_and_belongs_to_many || (reflection.macro == :has_many && reflection.options[:through])
- @aliased_join_table_name = reflection.macro == :has_and_belongs_to_many ? reflection.options[:join_table] : parent.active_record.reflect_on_association(reflection.options[:through]).klass.table_name
+ @aliased_join_table_name = reflection.macro == :has_and_belongs_to_many ? reflection.options[:join_table] : reflection.through_reflection.klass.table_name
unless join_dependency.table_aliases[aliased_join_table_name].zero?
@aliased_join_table_name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}_join"
table_index = join_dependency.table_aliases[aliased_join_table_name]
View
2  activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -72,7 +72,7 @@ def construct_conditions
when :belongs_to, :has_many
"#{@reflection.through_reflection.table_name}.#{@reflection.through_reflection.primary_key_name} = #{@owner.quoted_id}"
else
- raise ActiveRecordError, "Invalid source reflection macro :#{@reflection.source_reflection.macro} for has_many #{@reflection.name}, :through => #{@reflection.through_reflection.name}"
+ raise ActiveRecordError, "Invalid source reflection macro :#{@reflection.source_reflection.macro} for has_many #{@reflection.name}, :through => #{@reflection.through_reflection.name}. Use :source to specify the source reflection."
end
end
conditions << " AND (#{sql_conditions})" if sql_conditions
View
9 activerecord/lib/active_record/reflection.rb
@@ -144,14 +144,11 @@ def through_reflection
@through_reflection ||= options[:through] ? active_record.reflect_on_association(options[:through]) : false
end
- # Gets an array of possible :through reflection names
+ # Gets an array of possible :through source reflection names
#
# [singularized, pluralized]
def source_reflection_names
- @source_reflection_names ||= (options[:class_name] ?
- [options[:class_name].underscore, options[:class_name].underscore.pluralize] :
- [name.to_s.singularize, name]
- ).collect { |n| n.to_sym }
+ @source_reflection_names ||= (options[:source] ? [options[:source]] : [name.to_s.singularize, name]).collect { |n| n.to_sym }
end
# Gets the source of the through reflection. It checks both a singularized and pluralized form for :belongs_to or :has_many.
@@ -173,7 +170,7 @@ def check_validity!
end
if source_reflection.nil?
- raise HasManyThroughSourceAssociationNotFoundError.new(through_reflection, source_reflection_names)
+ raise HasManyThroughSourceAssociationNotFoundError.new(self)
end
if source_reflection.options[:polymorphic]
View
4 activerecord/test/associations_cascaded_eager_loading_test.rb
@@ -87,7 +87,7 @@ def test_eager_association_loading_with_belongs_to_sti
end
def test_eager_association_loading_with_multiple_stis_and_order
- author = Author.find(:first, :include => { :posts => [ :special_comments , :very_special_comment ] }, :order => 'authors.name, special_comments.body, very_special_comments.body', :conditions => 'posts.id = 4')
+ author = Author.find(:first, :include => { :posts => [ :special_comments , :very_special_comment ] }, :order => 'authors.name, comments.body, very_special_comments_posts.body', :conditions => 'posts.id = 4')
assert_equal authors(:david), author
assert_no_queries do
author.posts.first.special_comments
@@ -96,7 +96,7 @@ def test_eager_association_loading_with_multiple_stis_and_order
end
def test_eager_association_loading_of_stis_with_multiple_references
- authors = Author.find(:all, :include => { :posts => { :special_comments => { :post => [ :special_comments, :very_special_comment ] } } }, :order => 'special_comments.body, very_special_comments.body', :conditions => 'posts.id = 4')
+ authors = Author.find(:all, :include => { :posts => { :special_comments => { :post => [ :special_comments, :very_special_comment ] } } }, :order => 'comments.body, very_special_comments_posts.body', :conditions => 'posts.id = 4')
assert_equal [authors(:david)], authors
assert_no_queries do
authors.first.posts.first.special_comments.first.post.special_comments
View
2  activerecord/test/fixtures/author.rb
@@ -4,7 +4,7 @@ class Author < ActiveRecord::Base
has_many :posts_with_categories, :include => :categories, :class_name => "Post"
has_many :posts_with_comments_and_categories, :include => [ :comments, :categories ], :order => "posts.id", :class_name => "Post"
has_many :comments, :through => :posts
- has_many :funky_comments, :through => :posts, :class_name => 'Comment'
+ has_many :funky_comments, :through => :posts, :source => :comments
has_many :special_posts, :class_name => "Post"
has_many :hello_posts, :class_name => "Post", :conditions=>"\#{aliased_table_name}.body = 'hello'"
View
4 activerecord/test/fixtures/post.rb
@@ -28,12 +28,12 @@ def add_joins_and_select
end
end
- has_many :funky_tags, :through => :taggings, :class_name => 'Tag'
+ has_many :funky_tags, :through => :taggings, :source => :tag
has_many :super_tags, :through => :taggings
has_one :tagging, :as => :taggable
has_many :invalid_taggings, :as => :taggable, :class_name => "Tagging", :conditions => 'taggings.id < 0'
- has_many :invalid_tags, :through => :invalid_taggings, :class_name => "Tag"
+ has_many :invalid_tags, :through => :invalid_taggings, :source => :tag
has_many :categorizations, :foreign_key => :category_id
has_many :authors, :through => :categorizations
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