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Fixed eager loading problems with single-table inheritance [Rick Olso…

…n] Added smarter table aliasing for eager associations for multiple self joins [Rick Olson] (closes #3580)

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3776 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
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commit 4f00c70580e376691bd1d6c1f9d09efbaa7bf9c9 1 parent 84b8920
@dhh dhh authored
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11 activerecord/CHANGELOG
@@ -1,5 +1,16 @@
*SVN*
+* Added smarter table aliasing for eager associations for multiple self joins #3580 [Rick Olson]
+
+ * The first time a table is referenced in a join, no alias is used.
+ * After that, the parent table name and the reflection name are used.
+
+ Tree.find(:all, :include => :children) # LEFT OUTER JOIN trees AS tress_children ...
+
+ * Any additional join references get a numerical suffix like '_2', '_3', etc.
+
+* Fixed eager loading problems with single-table inheritance #3580 [Rick Olson]. Post.find(:all, :include => :special_comments) now returns all posts, and any special comments that the posts may have. And made STI work with has_many :through and polymorphic belongs_to.
+
* Added cascading eager loading that allows for queries like Author.find(:all, :include=> { :posts=> :comments }), which will fetch all authors, their posts, and the comments belonging to those posts in a single query (using LEFT OUTER JOIN) #3913 [anna@wota.jp]. Examples:
# cascaded in two levels
View
101 activerecord/lib/active_record/associations.rb
@@ -932,7 +932,6 @@ def construct_counter_sql_with_included_associations(options, join_dependency)
sql << "#{options[:joins]} " if options[:joins]
add_conditions!(sql, options[:conditions])
- add_sti_conditions!(sql, join_dependency)
add_limited_ids_condition!(sql, options, join_dependency) if !using_limitable_reflections?(join_dependency.reflections) && options[:limit]
add_limit!(sql, options) if using_limitable_reflections?(join_dependency.reflections)
@@ -950,7 +949,6 @@ def construct_finder_sql_with_included_associations(options, join_dependency)
sql << "#{options[:joins]} " if options[:joins]
add_conditions!(sql, options[:conditions])
- add_sti_conditions!(sql, join_dependency)
add_limited_ids_condition!(sql, options, join_dependency) if !using_limitable_reflections?(join_dependency.reflections) && options[:limit]
sql << "ORDER BY #{options[:order]} " if options[:order]
@@ -1011,41 +1009,6 @@ def using_limitable_reflections?(reflections)
reflections.reject { |r| [ :belongs_to, :has_one ].include?(r.macro) }.length.zero?
end
- def join_depended_type_condition (klass, join_dependency)
- aliased_table_name = join_dependency.aliased_table_names_for(klass.table_name).last || klass.table_name
- quoted_inheritance_column = connection.quote_column_name(klass.inheritance_column)
- type_condition = klass.subclasses.inject(sti_condition(klass, aliased_table_name, quoted_inheritance_column)) do |condition, subclass|
- condition << " OR #{sti_condition subclass, aliased_table_name, quoted_inheritance_column}"
- end
-
- " (#{type_condition}) "
- end
-
- def sti_condition(klass, table_name, inheritance_column)
- "(#{table_name}.#{inheritance_column} = '#{klass.name.demodulize}' OR #{table_name}.#{inheritance_column} IS NULL)"
- end
-
- #def join_depended_type_condition (klass, join_dependency)
- # aliased_table_name = join_dependency.aliased_table_names_for(klass.table_name).first || klass.table_name
- # quoted_inheritance_column = connection.quote_column_name(klass.inheritance_column)
- # type_condition = klass.subclasses.inject("#{aliased_table_name}.#{quoted_inheritance_column} = '#{klass.name.demodulize}' ") do |condition, subclass|
- # condition << "OR #{aliased_table_name}.#{quoted_inheritance_column} = '#{subclass.name.demodulize}' "
- # end
- #
- # " (#{type_condition}) "
- #end
-
- def add_sti_conditions!(sql, join_dependency)
- reflections = join_dependency.reflections
- sti_conditions = reflections.collect do |reflection|
- join_depended_type_condition(reflection.klass, join_dependency) unless reflection.klass.descends_from_active_record?
- end.compact
-
- unless sti_conditions.empty?
- sql << condition_word(sql) + sti_conditions.join(" AND ")
- end
- end
-
def column_aliases(join_dependency)
join_dependency.joins.collect{|join| join.column_names_with_alias.collect{|column_name, aliased_name|
"#{join.aliased_table_name}.#{connection.quote_column_name column_name} AS #{aliased_name}"}}.flatten.join(", ")
@@ -1078,7 +1041,7 @@ def create_extension_module(association_id, extension)
end
class JoinDependency
- attr_reader :joins, :reflections
+ attr_reader :joins, :reflections, :table_aliases
def initialize(base, associations)
@joins = [JoinBase.new(base)]
@@ -1086,6 +1049,8 @@ def initialize(base, 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
@@ -1228,26 +1193,65 @@ def initialize(reflection, join_dependency, parent = nil)
@parent = parent
@reflection = reflection
@aliased_prefix = "t#{ join_dependency.joins.size }"
- @aliased_table_name = join_dependency.aliased_table_names_for(table_name).empty? ? table_name : @aliased_prefix
+ @aliased_table_name = table_name # start with the table name
+ unless join_dependency.table_aliases[aliased_table_name].zero?
+ # if the table name has been used, then use an alias
+ # if the alias has been used, add a '_n' suffix to the end.
+ @aliased_table_name = "#{parent.table_name}_#{reflection.name}_#{join_dependency.table_aliases[aliased_table_name]}".gsub(/_1$/, '')
+ end
+ join_dependency.table_aliases[aliased_table_name] += 1
end
def association_join
- case reflection.macro
+ join = case reflection.macro
when :has_and_belongs_to_many
join_table_name =
" LEFT OUTER JOIN %s ON %s.%s = %s.%s " % [
options[:join_table], options[:join_table],
options[:foreign_key] || reflection.active_record.to_s.classify.foreign_key,
reflection.active_record.table_name, reflection.active_record.primary_key] +
- " LEFT OUTER JOIN %s ON %s.%s = %s.%s " % [
- aliased_table_name, aliased_table_name, klass.primary_key,
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [
+ table_name, aliased_table_name, aliased_table_name, klass.primary_key,
options[:join_table], options[:association_foreign_key] || klass.table_name.classify.foreign_key
]
when :has_many, :has_one
- " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [table_name, aliased_table_name,
- aliased_table_name, options[:foreign_key] || reflection.active_record.to_s.classify.foreign_key,
- parent.aliased_table_name, parent.primary_key
- ]
+ case
+ when reflection.macro == :has_many && reflection.options[:through]
+ through_reflection = parent.active_record.reflect_on_association(reflection.options[:through])
+ aliased_through_table = "#{parent.table_name}_#{through_reflection.klass.table_name}"
+ if through_reflection.options[:as] # has_many :through against a polymorphic join
+ polymorphic_foreign_key = through_reflection.options[:as].to_s + '_id'
+ polymorphic_foreign_type = through_reflection.options[:as].to_s + '_type'
+
+ " LEFT OUTER JOIN %s AS %s ON (%s.%s = %s.%s AND %s.%s = %s) " % [through_reflection.klass.table_name, aliased_through_table,
+ aliased_through_table, polymorphic_foreign_key,
+ parent.aliased_table_name, parent.primary_key,
+ aliased_through_table, polymorphic_foreign_type, reflection.klass.quote(parent.active_record.base_class.name)] +
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [table_name, aliased_table_name,
+ aliased_table_name, primary_key, aliased_through_table, options[:foreign_key] || reflection.klass.to_s.classify.foreign_key
+ ]
+ else # has_many :through against a normal join
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [through_reflection.klass.table_name, aliased_through_table,
+ aliased_through_table, through_reflection.options[:foreign_key] || through_reflection.active_record.to_s.classify.foreign_key,
+ parent.aliased_table_name, parent.primary_key] +
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [table_name, aliased_table_name,
+ aliased_table_name, primary_key, aliased_through_table, options[:foreign_key] || reflection.klass.to_s.classify.foreign_key
+ ]
+ end
+
+ when reflection.macro == :has_many && reflection.options[:as]
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s AND %s.%s = %s" % [table_name, aliased_table_name,
+ aliased_table_name, "#{reflection.options[:as]}_id",
+ parent.aliased_table_name, parent.primary_key,
+ aliased_table_name, "#{reflection.options[:as]}_type",
+ reflection.klass.quote(parent.active_record.base_class.name)
+ ]
+ else
+ " LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [table_name, aliased_table_name,
+ aliased_table_name, options[:foreign_key] || reflection.active_record.to_s.classify.foreign_key,
+ parent.aliased_table_name, parent.primary_key
+ ]
+ end
when :belongs_to
" LEFT OUTER JOIN %s AS %s ON %s.%s = %s.%s " % [table_name, aliased_table_name,
aliased_table_name, reflection.klass.primary_key,
@@ -1256,6 +1260,11 @@ def association_join
else
""
end
+ join << %(AND %s."%s" = %s ) % [
+ aliased_table_name,
+ reflection.active_record.inheritance_column,
+ reflection.klass.quote(klass.name)] unless join.blank? || reflection.klass.descends_from_active_record?
+ join
end
end
end
View
22 activerecord/test/abstract_unit.rb
@@ -29,6 +29,19 @@ def assert_date_from_db(expected, actual, message = nil)
assert_equal expected.to_s, actual.to_s, message
end
end
+
+ def assert_no_queries
+ ActiveRecord::Base.connection.class.class_eval do
+ self.query_count = 0
+ alias_method :execute, :execute_with_query_counting
+ end
+ yield
+ ensure
+ ActiveRecord::Base.connection.class.class_eval do
+ alias_method :execute, :execute_without_query_counting
+ end
+ assert_equal 0, ActiveRecord::Base.connection.query_count, "1 or more queries were executed"
+ end
end
def current_adapter?(type)
@@ -36,5 +49,14 @@ def current_adapter?(type)
ActiveRecord::Base.connection.instance_of?(ActiveRecord::ConnectionAdapters.const_get(type))
end
+ActiveRecord::Base.connection.class.class_eval do
+ cattr_accessor :query_count
+ alias_method :execute_without_query_counting, :execute
+ def execute_with_query_counting(sql, name = nil)
+ self.query_count += 1
+ execute_without_query_counting(sql, name)
+ end
+end
+
#ActiveRecord::Base.logger = Logger.new(STDOUT)
#ActiveRecord::Base.colorize_logging = false
View
26 activerecord/test/associations_cascaded_eager_loading_test.rb
@@ -56,23 +56,33 @@ def test_eager_association_loading_with_cascaded_two_levels_with_condition
def test_eager_association_loading_with_acts_as_tree
roots = TreeMixin.find(:all, :include=>"children", :conditions=>"mixins.parent_id IS NULL", :order=>"mixins.id")
assert_equal [mixins(:tree_1), mixins(:tree2_1), mixins(:tree3_1)], roots
- assert_equal 2, roots[0].children.size
- assert_equal 0, roots[1].children.size
- assert_equal 0, roots[2].children.size
+ assert_no_queries do
+ assert_equal 2, roots[0].children.size
+ assert_equal 0, roots[1].children.size
+ assert_equal 0, roots[2].children.size
+ end
end
def test_eager_association_loading_with_cascaded_three_levels_by_ping_pong
firms = Firm.find(:all, :include=>{:account=>{:firm=>:account}}, :order=>"companies.id")
assert_equal 2, firms.size
assert_equal firms.first.account, firms.first.account.firm.account
- assert_equal companies(:first_firm).account, firms.first.account.firm.account
- assert_equal companies(:first_firm).account.firm.account, firms.first.account.firm.account
+ assert_equal companies(:first_firm).account, assert_no_queries { firms.first.account.firm.account }
+ assert_equal companies(:first_firm).account.firm.account, assert_no_queries { firms.first.account.firm.account }
end
- def test_eager_association_loading_with_sti
+ def test_eager_association_loading_with_has_many_sti
topics = Topic.find(:all, :include => :replies, :order => 'topics.id')
assert_equal [topics(:first), topics(:second)], topics
- assert_equal 1, topics[0].replies.size
- assert_equal 0, topics[1].replies.size
+ assert_no_queries do
+ assert_equal 1, topics[0].replies.size
+ assert_equal 0, topics[1].replies.size
+ end
+ end
+
+ def test_eager_association_loading_with_belongs_to_sti
+ replies = Reply.find(:all, :include => :topic, :order => 'topics.id')
+ assert_equal [topics(:second)], replies
+ assert_equal topics(:first), assert_no_queries { replies.first.topic }
end
end
View
8 activerecord/test/associations_go_eager_test.rb
@@ -94,13 +94,13 @@ def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_cond
def test_eager_association_loading_with_belongs_to_and_limit_and_multiple_associations
posts = Post.find(:all, :include => [:author, :very_special_comment], :limit => 1, :order => 'posts.id')
assert_equal 1, posts.length
- assert_equal [3], posts.collect { |p| p.id }
+ assert_equal [1], posts.collect { |p| p.id }
end
def test_eager_association_loading_with_belongs_to_and_limit_and_offset_and_multiple_associations
posts = Post.find(:all, :include => [:author, :very_special_comment], :limit => 1, :offset => 1, :order => 'posts.id')
assert_equal 1, posts.length
- assert_equal [4], posts.collect { |p| p.id }
+ assert_equal [2], posts.collect { |p| p.id }
end
def test_eager_with_has_many_through
@@ -108,8 +108,8 @@ def test_eager_with_has_many_through
posts_with_author = people(:michael).posts.find(:all, :include => :author )
posts_with_comments_and_author = people(:michael).posts.find(:all, :include => [ :comments, :author ])
assert_equal 2, posts_with_comments.inject(0) { |sum, post| sum += post.comments.size }
- assert_equal authors(:david), posts_with_author.first.author
- assert_equal authors(:david), posts_with_comments_and_author.first.author
+ assert_equal authors(:david), assert_no_queries { posts_with_author.first.author }
+ assert_equal authors(:david), assert_no_queries { posts_with_comments_and_author.first.author }
end
def test_eager_with_has_many_and_limit
View
29 activerecord/test/associations_join_model_test.rb
@@ -81,7 +81,34 @@ def test_create_polymorphic_has_one_with_scope
def test_has_many_with_piggyback
assert_equal "2", categories(:sti_test).authors.first.post_id.to_s
end
-
+
+ def test_include_has_many_through
+ posts = Post.find(:all, :order => 'posts.id')
+ posts_with_authors = Post.find(:all, :include => :authors, :order => 'posts.id')
+ assert_equal posts.length, posts_with_authors.length
+ posts.length.times do |i|
+ assert_equal posts[i].authors.length, assert_no_queries { posts_with_authors[i].authors.length }
+ end
+ end
+
+ def test_include_polymorphic_has_many_through
+ posts = Post.find(:all, :order => 'posts.id')
+ posts_with_tags = Post.find(:all, :include => :tags, :order => 'posts.id')
+ assert_equal posts.length, posts_with_tags.length
+ posts.length.times do |i|
+ assert_equal posts[i].tags.length, assert_no_queries { posts_with_tags[i].tags.length }
+ end
+ end
+
+ def test_include_polymorphic_has_many
+ posts = Post.find(:all, :order => 'posts.id')
+ posts_with_taggings = Post.find(:all, :include => :taggings, :order => 'posts.id')
+ assert_equal posts.length, posts_with_taggings.length
+ posts.length.times do |i|
+ assert_equal posts[i].taggings.length, assert_no_queries { posts_with_taggings[i].taggings.length }
+ end
+ end
+
def test_has_many_find_all
assert_equal [categories(:general)], authors(:david).categories.find(:all)
end
View
4 activerecord/test/base_test.rb
@@ -567,7 +567,7 @@ def test_default_values_on_empty_strings
end
def test_equality
- assert_equal Topic.find(1), Topic.find(2).parent
+ assert_equal Topic.find(1), Topic.find(2).topic
end
def test_equality_of_new_records
@@ -575,7 +575,7 @@ def test_equality_of_new_records
end
def test_hashing
- assert_equal [ Topic.find(1) ], [ Topic.find(2).parent ] & [ Topic.find(1) ]
+ assert_equal [ Topic.find(1) ], [ Topic.find(2).topic ] & [ Topic.find(1) ]
end
def test_destroy_new_record
View
3  activerecord/test/finder_test.rb
@@ -1,6 +1,7 @@
require 'abstract_unit'
require 'fixtures/company'
require 'fixtures/topic'
+require 'fixtures/reply'
require 'fixtures/entrant'
require 'fixtures/developer'
require 'fixtures/post'
@@ -92,7 +93,7 @@ def test_unexisting_record_exception_handling
Topic.find(1).parent
}
- Topic.find(2).parent
+ Topic.find(2).topic
end
def test_find_only_some_columns
View
2  activerecord/test/fixtures/topic.rb
@@ -6,7 +6,7 @@ class Topic < ActiveRecord::Base
before_destroy :destroy_children
def parent
- self.class.find(parent_id)
+ Topic.find(parent_id)
end
protected
View
1  activerecord/test/fixtures/topics.yml
@@ -19,3 +19,4 @@ second:
approved: true
replies_count: 2
parent_id: 1
+ type: Reply
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