Foxy fixtures. Adapter#disable_referential_integrity. Closes #9981.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8036 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 295 insertions, 15 deletions

diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index b314340f0c..c9fc87756d 100755
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -215,6 +215,199 @@ end
 #      the results of your transaction until Active Record supports nested transactions or savepoints (in progress.)
 #   2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM.
 #      Use InnoDB, MaxDB, or NDB instead.
+#
+# = Advanced YAML Fixtures
+#
+# YAML fixtures that don't specify an ID get some extra features:
+#
+# * Stable, autogenerated ID's
+# * Label references for associations (belongs_to, has_one, has_many)
+# * HABTM associations as inline lists
+# * Autofilled timestamp columns
+# * Fixture label interpolation
+# * Support for YAML defaults
+#
+# == Stable, autogenerated ID's
+#
+# Here, have a monkey fixture:
+#
+#   george:
+#     id: 1
+#     name: George the Monkey
+#
+#   reginald:
+#     id: 2
+#     name: Reginald the Pirate
+#
+# Each of these fixtures has two unique identifiers: one for the database
+# and one for the humans. Why don't we generate the primary key instead?
+# Hashing each fixture's label yields a consistent ID:
+#
+#   george: # generated id: 503576764
+#     name: George the Monkey
+#
+#   reginald: # generated id: 324201669
+#     name: Reginald the Pirate
+#
+# ActiveRecord looks at the fixture's model class, discovers the correct
+# primary key, and generates it right before inserting the fixture
+# into the database.
+#
+# The generated ID for a given label is constant, so we can discover
+# any fixture's ID without loading anything, as long as we know the label.
+#
+# == Label references for associations (belongs_to, has_one, has_many)
+#
+# Specifying foreign keys in fixtures can be very fragile, not to
+# mention difficult to read. Since ActiveRecord can figure out the ID of
+# and fixture from its label, you can specify FK's by label instead of ID.
+#
+# === belongs_to
+#
+# Let's break out some more monkeys and pirates.
+#
+#   ### in pirates.yml
+#
+#   reginald:
+#     id: 1
+#     name: Reginald the Pirate
+#     monkey_id: 1
+#
+#   ### in monkeys.yml
+#
+#   george:
+#     id: 1
+#     name: George the Monkey
+#     pirate_id: 1
+#
+# Add a few more monkeys and pirates and break this into multiple files,
+# and it gets pretty hard to keep track of what's going on. Let's
+# use labels instead of ID's:
+#
+#   ### in pirates.yml
+#
+#   reginald:
+#     name: Reginald the Pirate
+#     monkey: george
+#
+#   ### in monkeys.yml
+#
+#   george:
+#     name: George the Monkey
+#     pirate: reginald
+#
+# Pow! All is made clear. ActiveRecord reflects on the fixture's model class,
+# finds all the +belongs_to+ associations, and allows you to specify
+# a target *label* for the *association* (monkey: george) rather than
+# a target *id* for the *FK* (monkey_id: 1).
+#
+# === has_and_belongs_to_many
+#
+# Time to give our monkey some fruit.
+#
+#   ### in monkeys.yml
+#
+#   george:
+#     id: 1
+#     name: George the Monkey
+#     pirate_id: 1
+#
+#   ### in fruits.yml
+#
+#   apple:
+#     id: 1
+#     name: apple
+#
+#   orange:
+#     id: 2
+#     name: orange
+#
+#   grape:
+#     id: 3
+#     name: grape
+#
+#   ### in fruits_monkeys.yml
+#
+#   apple_george:
+#     fruit_id: 1
+#     monkey_id: 1
+#
+#   orange_george:
+#     fruit_id: 2
+#     monkey_id: 1
+#
+#   grape_george:
+#     fruit_id: 3
+#     monkey_id: 1
+#
+# Let's make the HABTM fixture go away.
+#
+#   ### in monkeys.yml
+#
+#   george:
+#     name: George the Monkey
+#     pirate: reginald
+#     fruits: apple, orange, grape
+#
+#   ### in fruits.yml
+#
+#   apple:
+#     name: apple
+#
+#   orange:
+#     name: orange
+#
+#   grape:
+#     name: grape
+#
+# Zap! No more fruits_monkeys.yml file. We've specified the list of fruits
+# on George's fixture, but we could've just as easily specified a list
+# of monkeys on each fruit. As with +belongs_to+, ActiveRecord reflects on
+# the fixture's model class and discovers the +has_and_belongs_to_many+
+# associations.
+#
+# == Autofilled timestamp columns
+#
+# If your table/model specifies any of ActiveRecord's
+# standard timestamp columns (created_at, created_on, updated_at, updated_on),
+# they will automatically be set to Time.now.
+#
+# If you've set specific values, they'll be left alone.
+#
+# == Fixture label interpolation
+#
+# The label of the current fixture is always available as a column value:
+#
+#   geeksomnia:
+#     name: Geeksomnia's Account
+#     subdomain: $LABEL
+#
+# Also, sometimes (like when porting older join table fixtures) you'll need
+# to be able to get ahold of the identifier for a given label. ERB
+# to the rescue:
+#
+#   george_reginald:
+#     monkey_id: <%= Fixtures.identify(:reginald) %>
+#     pirate_id: <%= Fixtures.identify(:george) %>
+#
+# == Support for YAML defaults
+#
+# You probably already know how to use YAML to set and reuse defaults in
+# your +database.yml+ file,. You can use the same technique in your fixtures:
+#
+#   DEFAULTS: &DEFAULTS
+#     created_on: <%= 3.weeks.ago.to_s(:db) %>
+#
+#   first:
+#     name: Smurf
+#     <<: *DEFAULTS
+#
+#   second:
+#     name: Fraggle
+#     <<: *DEFAULTS
+#
+# Any fixture labeled "DEFAULTS" is safely ignored.
+
 class Fixtures < YAML::Omap
   DEFAULT_FILTER_RE = /\.ya?ml$/
 
@@ -279,32 +472,41 @@ class Fixtures < YAML::Omap
 
     unless table_names_to_fetch.empty?
       ActiveRecord::Base.silence do
-        fixtures_map = {}
+        connection.disable_referential_integrity do
+          fixtures_map = {}
 
-        fixtures = table_names_to_fetch.map do |table_name|
-          fixtures_map[table_name] = Fixtures.new(connection, File.split(table_name.to_s).last, class_names[table_name.to_sym], File.join(fixtures_directory, table_name.to_s))
-        end
+          fixtures = table_names_to_fetch.map do |table_name|
+            fixtures_map[table_name] = Fixtures.new(connection, File.split(table_name.to_s).last, class_names[table_name.to_sym], File.join(fixtures_directory, table_name.to_s))
+          end
 
-        all_loaded_fixtures.update(fixtures_map)
+          all_loaded_fixtures.update(fixtures_map)
 
-        connection.transaction(Thread.current['open_transactions'].to_i == 0) do
-          fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures }
-          fixtures.each { |fixture| fixture.insert_fixtures }
+          connection.transaction(Thread.current['open_transactions'].to_i == 0) do
+            fixtures.reverse.each { |fixture| fixture.delete_existing_fixtures }
+            fixtures.each { |fixture| fixture.insert_fixtures }
 
-          # Cap primary key sequences to max(pk).
-          if connection.respond_to?(:reset_pk_sequence!)
-            table_names.each do |table_name|
-              connection.reset_pk_sequence!(table_name)
+            # Cap primary key sequences to max(pk).
+            if connection.respond_to?(:reset_pk_sequence!)
+              table_names.each do |table_name|
+                connection.reset_pk_sequence!(table_name)
+              end
             end
           end
-        end
 
-        cache_fixtures(connection, fixtures)
+          cache_fixtures(connection, fixtures)
+        end
       end
     end
     cached_fixtures(connection, table_names)
   end
 
+  # Returns a consistent identifier for +label+. This will always
+  # be a positive integer, and will always be the same for a given
+  # label, assuming the same OS, platform, and version of Ruby.
+  def self.identify(label)
+    label.to_s.hash.abs
+  end
+
   attr_reader :table_name
 
   def initialize(connection, table_name, class_name, fixture_path, file_filter = DEFAULT_FILTER_RE)
@@ -322,12 +524,90 @@ class Fixtures < YAML::Omap
   end
 
   def insert_fixtures
-    values.each do |fixture|
+    now = ActiveRecord::Base.default_timezone == :utc ? Time.now.utc : Time.now
+    now = now.to_s(:db)
+
+    # allow a standard key to be used for doing defaults in YAML
+    delete(assoc("DEFAULTS"))
+
+    # track any join tables we need to insert later
+    habtm_fixtures = Hash.new do |h, habtm|
+      h[habtm] = HabtmFixtures.new(@connection, habtm.options[:join_table], nil, nil)
+    end
+
+    each do |label, fixture|
+      row = fixture.to_hash
+
+      if model_class && model_class < ActiveRecord::Base && !row[primary_key_name]
+        # fill in timestamp columns if they aren't specified
+        timestamp_column_names.each do |name|
+          row[name] = now unless row.key?(name)
+        end
+
+        # interpolate the fixture label
+        row.each do |key, value|
+          row[key] = label if value == "$LABEL"
+        end
+
+        # generate a primary key
+        row[primary_key_name] = Fixtures.identify(label)
+
+        model_class.reflect_on_all_associations.each do |association|
+          case association.macro
+          when :belongs_to
+            if value = row.delete(association.name.to_s)
+              fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s
+              row[fk_name] = Fixtures.identify(value)
+            end
+          when :has_and_belongs_to_many
+            if (targets = row.delete(association.name.to_s))
+              targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
+              join_fixtures = habtm_fixtures[association]
+
+              targets.each do |target|
+                join_fixtures["#{label}_#{target}"] = Fixture.new(
+                  { association.primary_key_name => Fixtures.identify(label),
+                    association.association_foreign_key => Fixtures.identify(target) }, nil)
+              end
+            end
+          end
+        end
+      end
+
       @connection.insert_fixture(fixture, @table_name)
     end
+
+    # insert any HABTM join tables we discovered
+    habtm_fixtures.values.each do |fixture|
+      fixture.delete_existing_fixtures
+      fixture.insert_fixtures
+    end
   end
 
   private
+    class HabtmFixtures < ::Fixtures #:nodoc:
+      def read_fixture_files; end
+    end
+
+    def model_class
+      @model_class ||= @class_name.is_a?(Class) ?
+        @class_name : @class_name.constantize rescue nil
+    end
+
+    def primary_key_name
+      @primary_key_name ||= model_class && model_class.primary_key
+    end
+
+    def timestamp_column_names
+      @timestamp_column_names ||= %w(created_at created_on updated_at updated_on).select do |name|
+        column_names.include?(name)
+      end
+    end
+
+    def column_names
+      @column_names ||= @connection.columns(@table_name).collect(&:name)
+    end
+
     def read_fixture_files
       if File.file?(yaml_file_path)
         read_yaml_fixture_files