applies new string literal convention in activerecord/lib

The current code base is not uniform. After some discussion,
we have chosen to go with double quotes by default.

118 files changed, 840 insertions, 840 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index baa497dc98..fb7b8df01d 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -21,13 +21,13 @@
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #++
 
-require 'active_support'
-require 'active_support/rails'
-require 'active_model'
-require 'arel'
+require "active_support"
+require "active_support/rails"
+require "active_model"
+require "arel"
 
-require 'active_record/version'
-require 'active_record/attribute_set'
+require "active_record/version"
+require "active_record/attribute_set"
 
 module ActiveRecord
   extend ActiveSupport::Autoload
@@ -46,7 +46,7 @@ module ActiveRecord
   autoload :Integration
   autoload :LegacyYamlAdapter
   autoload :Migration
-  autoload :Migrator, 'active_record/migration'
+  autoload :Migrator, "active_record/migration"
   autoload :ModelSchema
   autoload :NestedAttributes
   autoload :NoTouching
@@ -56,7 +56,7 @@ module ActiveRecord
   autoload :Querying
   autoload :CollectionCacheKey
   autoload :ReadonlyAttributes
-  autoload :RecordInvalid, 'active_record/validations'
+  autoload :RecordInvalid, "active_record/validations"
   autoload :Reflection
   autoload :RuntimeRegistry
   autoload :Sanitization
@@ -76,9 +76,9 @@ module ActiveRecord
   autoload :SecureToken
 
   eager_autoload do
-    autoload :ActiveRecordError, 'active_record/errors'
-    autoload :ConnectionNotEstablished, 'active_record/errors'
-    autoload :ConnectionAdapters, 'active_record/connection_adapters/abstract_adapter'
+    autoload :ActiveRecordError, "active_record/errors"
+    autoload :ConnectionNotEstablished, "active_record/errors"
+    autoload :ConnectionAdapters, "active_record/connection_adapters/abstract_adapter"
 
     autoload :Aggregations
     autoload :Associations
@@ -90,7 +90,7 @@ module ActiveRecord
     autoload :AssociationRelation
     autoload :NullRelation
 
-    autoload_under 'relation' do
+    autoload_under "relation" do
       autoload :QueryMethods
       autoload :FinderMethods
       autoload :Calculations
@@ -104,8 +104,8 @@ module ActiveRecord
   end
 
   module Coders
-    autoload :YAMLColumn, 'active_record/coders/yaml_column'
-    autoload :JSON, 'active_record/coders/json'
+    autoload :YAMLColumn, "active_record/coders/yaml_column"
+    autoload :JSON, "active_record/coders/json"
   end
 
   module AttributeMethods
@@ -153,13 +153,13 @@ module ActiveRecord
     extend ActiveSupport::Autoload
 
     autoload :DatabaseTasks
-    autoload :SQLiteDatabaseTasks, 'active_record/tasks/sqlite_database_tasks'
-    autoload :MySQLDatabaseTasks,  'active_record/tasks/mysql_database_tasks'
+    autoload :SQLiteDatabaseTasks, "active_record/tasks/sqlite_database_tasks"
+    autoload :MySQLDatabaseTasks,  "active_record/tasks/mysql_database_tasks"
     autoload :PostgreSQLDatabaseTasks,
-      'active_record/tasks/postgresql_database_tasks'
+      "active_record/tasks/postgresql_database_tasks"
   end
 
-  autoload :TestFixtures, 'active_record/fixtures'
+  autoload :TestFixtures, "active_record/fixtures"
 
   def self.eager_load!
     super
@@ -176,5 +176,5 @@ ActiveSupport.on_load(:active_record) do
 end
 
 ActiveSupport.on_load(:i18n) do
-  I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml'
+  I18n.load_path << File.dirname(__FILE__) + "/active_record/locale/en.yml"
 end
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb
index c91b5d3fe3..61a26cf914 100644
--- a/activerecord/lib/active_record/associations.rb
+++ b/activerecord/lib/active_record/associations.rb
@@ -1,7 +1,7 @@
-require 'active_support/core_ext/enumerable'
-require 'active_support/core_ext/string/conversions'
-require 'active_support/core_ext/module/remove_method'
-require 'active_record/errors'
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/string/conversions"
+require "active_support/core_ext/module/remove_method"
+require "active_record/errors"
 
 module ActiveRecord
   class AssociationNotFoundError < ConfigurationError #:nodoc:
@@ -207,14 +207,14 @@ module ActiveRecord
     autoload :ThroughAssociation
 
     module Builder #:nodoc:
-      autoload :Association,           'active_record/associations/builder/association'
-      autoload :SingularAssociation,   'active_record/associations/builder/singular_association'
-      autoload :CollectionAssociation, 'active_record/associations/builder/collection_association'
+      autoload :Association,           "active_record/associations/builder/association"
+      autoload :SingularAssociation,   "active_record/associations/builder/singular_association"
+      autoload :CollectionAssociation, "active_record/associations/builder/collection_association"
 
-      autoload :BelongsTo,           'active_record/associations/builder/belongs_to'
-      autoload :HasOne,              'active_record/associations/builder/has_one'
-      autoload :HasMany,             'active_record/associations/builder/has_many'
-      autoload :HasAndBelongsToMany, 'active_record/associations/builder/has_and_belongs_to_many'
+      autoload :BelongsTo,           "active_record/associations/builder/belongs_to"
+      autoload :HasOne,              "active_record/associations/builder/has_one"
+      autoload :HasMany,             "active_record/associations/builder/has_many"
+      autoload :HasAndBelongsToMany, "active_record/associations/builder/has_and_belongs_to_many"
     end
 
     eager_autoload do
diff --git a/activerecord/lib/active_record/associations/alias_tracker.rb b/activerecord/lib/active_record/associations/alias_tracker.rb
index 021bc32237..3963008a76 100644
--- a/activerecord/lib/active_record/associations/alias_tracker.rb
+++ b/activerecord/lib/active_record/associations/alias_tracker.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/conversions'
+require "active_support/core_ext/string/conversions"
 
 module ActiveRecord
   module Associations
diff --git a/activerecord/lib/active_record/associations/association.rb b/activerecord/lib/active_record/associations/association.rb
index 62e867a353..74803d0ad5 100644
--- a/activerecord/lib/active_record/associations/association.rb
+++ b/activerecord/lib/active_record/associations/association.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/array/wrap'
+require "active_support/core_ext/array/wrap"
 
 module ActiveRecord
   module Associations
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
index f25bd7ca9f..6857929d61 100644
--- a/activerecord/lib/active_record/associations/builder/collection_association.rb
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -1,6 +1,6 @@
 # This class is inherited by the has_many and has_many_and_belongs_to_many association classes
 
-require 'active_record/associations'
+require "active_record/associations"
 
 module ActiveRecord::Associations::Builder # :nodoc:
   class CollectionAssociation < Association #:nodoc:
diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
index dd5fd607a2..33c8d4b8d6 100644
--- a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -94,7 +94,7 @@ module ActiveRecord::Associations::Builder # :nodoc:
 
     def middle_reflection(join_model)
       middle_name = [lhs_model.name.downcase.pluralize,
-                     association_name].join('_'.freeze).gsub('::'.freeze, '_'.freeze).to_sym
+                     association_name].join("_".freeze).gsub("::".freeze, "_".freeze).to_sym
       middle_options = middle_options join_model
 
       HasMany.create_reflection(lhs_model,
diff --git a/activerecord/lib/active_record/associations/has_many_through_association.rb b/activerecord/lib/active_record/associations/has_many_through_association.rb
index ddd0b59cc1..67510f18d4 100644
--- a/activerecord/lib/active_record/associations/has_many_through_association.rb
+++ b/activerecord/lib/active_record/associations/has_many_through_association.rb
@@ -146,7 +146,7 @@ module ActiveRecord
               stmt.from scope.klass.arel_table
               stmt.wheres = arel.constraints
 
-              count = scope.klass.connection.delete(stmt, 'SQL', scope.bound_attributes)
+              count = scope.klass.connection.delete(stmt, "SQL", scope.bound_attributes)
             end
           when :nullify
             count = scope.update_all(source_reflection.foreign_key => nil)
diff --git a/activerecord/lib/active_record/associations/join_dependency.rb b/activerecord/lib/active_record/associations/join_dependency.rb
index 491152bbcb..0f9ad77405 100644
--- a/activerecord/lib/active_record/associations/join_dependency.rb
+++ b/activerecord/lib/active_record/associations/join_dependency.rb
@@ -1,8 +1,8 @@
 module ActiveRecord
   module Associations
     class JoinDependency # :nodoc:
-      autoload :JoinBase,        'active_record/associations/join_dependency/join_base'
-      autoload :JoinAssociation, 'active_record/associations/join_dependency/join_association'
+      autoload :JoinBase,        "active_record/associations/join_dependency/join_base"
+      autoload :JoinAssociation, "active_record/associations/join_dependency/join_association"
 
       class Aliases # :nodoc:
         def initialize(tables)
@@ -154,7 +154,7 @@ module ActiveRecord
           class_name: join_root.base_klass.name
         }
 
-        message_bus.instrument('instantiation.active_record', payload) do
+        message_bus.instrument("instantiation.active_record", payload) do
           result_set.each { |row_hash|
             parent_key = primary_key ? row_hash[primary_key] : row_hash
             parent = parents[parent_key] ||= join_root.instantiate(row_hash, column_aliases)
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_association.rb b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
index bdf77009eb..a5705951f3 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_association.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_association.rb
@@ -1,4 +1,4 @@
-require 'active_record/associations/join_dependency/join_part'
+require "active_record/associations/join_dependency/join_part"
 
 module ActiveRecord
   module Associations
diff --git a/activerecord/lib/active_record/associations/join_dependency/join_base.rb b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
index 3a26c25737..fca20514d1 100644
--- a/activerecord/lib/active_record/associations/join_dependency/join_base.rb
+++ b/activerecord/lib/active_record/associations/join_dependency/join_base.rb
@@ -1,4 +1,4 @@
-require 'active_record/associations/join_dependency/join_part'
+require "active_record/associations/join_dependency/join_part"
 
 module ActiveRecord
   module Associations
diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb
index e64af84e1a..320d9dc952 100644
--- a/activerecord/lib/active_record/associations/preloader.rb
+++ b/activerecord/lib/active_record/associations/preloader.rb
@@ -42,16 +42,16 @@ module ActiveRecord
       extend ActiveSupport::Autoload
 
       eager_autoload do
-        autoload :Association,           'active_record/associations/preloader/association'
-        autoload :SingularAssociation,   'active_record/associations/preloader/singular_association'
-        autoload :CollectionAssociation, 'active_record/associations/preloader/collection_association'
-        autoload :ThroughAssociation,    'active_record/associations/preloader/through_association'
-
-        autoload :HasMany,             'active_record/associations/preloader/has_many'
-        autoload :HasManyThrough,      'active_record/associations/preloader/has_many_through'
-        autoload :HasOne,              'active_record/associations/preloader/has_one'
-        autoload :HasOneThrough,       'active_record/associations/preloader/has_one_through'
-        autoload :BelongsTo,           'active_record/associations/preloader/belongs_to'
+        autoload :Association,           "active_record/associations/preloader/association"
+        autoload :SingularAssociation,   "active_record/associations/preloader/singular_association"
+        autoload :CollectionAssociation, "active_record/associations/preloader/collection_association"
+        autoload :ThroughAssociation,    "active_record/associations/preloader/through_association"
+
+        autoload :HasMany,             "active_record/associations/preloader/has_many"
+        autoload :HasManyThrough,      "active_record/associations/preloader/has_many_through"
+        autoload :HasOne,              "active_record/associations/preloader/has_one"
+        autoload :HasOneThrough,       "active_record/associations/preloader/has_one_through"
+        autoload :BelongsTo,           "active_record/associations/preloader/belongs_to"
       end
 
       NULL_RELATION = Struct.new(:values, :where_clause, :joins_values).new({}, Relation::WhereClause.empty, [])
diff --git a/activerecord/lib/active_record/attribute/user_provided_default.rb b/activerecord/lib/active_record/attribute/user_provided_default.rb
index 4580813364..32b9c289bb 100644
--- a/activerecord/lib/active_record/attribute/user_provided_default.rb
+++ b/activerecord/lib/active_record/attribute/user_provided_default.rb
@@ -1,4 +1,4 @@
-require 'active_record/attribute'
+require "active_record/attribute"
 
 module ActiveRecord
   class Attribute # :nodoc:
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
index b96d8e9352..1cccb0852e 100644
--- a/activerecord/lib/active_record/attribute_assignment.rb
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -1,4 +1,4 @@
-require 'active_model/forbidden_attributes_protection'
+require "active_model/forbidden_attributes_protection"
 
 module ActiveRecord
   module AttributeAssignment
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index eadd73aab0..12699bb30b 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -1,7 +1,7 @@
-require 'active_support/core_ext/enumerable'
-require 'active_support/core_ext/string/filters'
-require 'mutex_m'
-require 'concurrent/map'
+require "active_support/core_ext/enumerable"
+require "active_support/core_ext/string/filters"
+require "mutex_m"
+require "concurrent/map"
 
 module ActiveRecord
   # = Active Record Attribute Methods
@@ -148,7 +148,7 @@ module ActiveRecord
       #   Person.attribute_method?(:age=)    # => true
       #   Person.attribute_method?(:nothing) # => false
       def attribute_method?(attribute)
-        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, '')))
+        super || (table_exists? && column_names.include?(attribute.to_s.sub(/=$/, "")))
       end
 
       # Returns an array of column names as strings if it's not an abstract class and
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index 0bcfa5f00d..50d7e1df7a 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -1,5 +1,5 @@
-require 'active_support/core_ext/module/attribute_accessors'
-require 'active_record/attribute_mutation_tracker'
+require "active_support/core_ext/module/attribute_accessors"
+require "active_record/attribute_mutation_tracker"
 
 module ActiveRecord
   module AttributeMethods
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index d28edfb003..162a564a49 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -1,4 +1,4 @@
-require 'set'
+require "set"
 
 module ActiveRecord
   module AttributeMethods
@@ -48,14 +48,14 @@ module ActiveRecord
       protected
 
       def attribute_method?(attr_name)
-        attr_name == 'id' || super
+        attr_name == "id" || super
       end
 
       module ClassMethods
         def define_method_attribute(attr_name)
           super
 
-          if attr_name == primary_key && attr_name != 'id'
+          if attr_name == primary_key && attr_name != "id"
             generated_attribute_methods.send(:alias_method, :id, primary_key)
           end
         end
@@ -98,7 +98,7 @@ module ActiveRecord
               pk = connection.schema_cache.primary_keys(table_name)
               suppress_composite_primary_key(pk)
             else
-              'id'
+              "id"
             end
           end
         end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index ab2ecaa7c5..a7310130fe 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -25,7 +25,7 @@ module ActiveRecord
         # Making it frozen means that it doesn't get duped when used to
         # key the @attributes in read_attribute.
         def define_method_attribute(name)
-          safe_name = name.unpack('h*'.freeze).first
+          safe_name = name.unpack("h*".freeze).first
           temp_method = "__temp__#{safe_name}"
 
           ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
@@ -49,7 +49,7 @@ module ActiveRecord
       # to a date object, like Date.new(2004, 12, 12)).
       def read_attribute(attr_name, &block)
         name = attr_name.to_s
-        name = self.class.primary_key if name == 'id'.freeze
+        name = self.class.primary_key if name == "id".freeze
         _read_attribute(name, &block)
       end
 
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index cbb4f0cff8..d7b5f8b262 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/strip'
+require "active_support/core_ext/string/strip"
 
 module ActiveRecord
   module AttributeMethods
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index 70c2d2f25d..e7f62197c3 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -11,7 +11,7 @@ module ActiveRecord
         protected
 
         def define_method_attribute=(name)
-          safe_name = name.unpack('h*'.freeze).first
+          safe_name = name.unpack("h*".freeze).first
           ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
 
           generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
@@ -44,7 +44,7 @@ module ActiveRecord
 
       def write_attribute_with_type_cast(attr_name, value, should_type_cast)
         attr_name = attr_name.to_s
-        attr_name = self.class.primary_key if attr_name == 'id' && self.class.primary_key
+        attr_name = self.class.primary_key if attr_name == "id" && self.class.primary_key
 
         if should_type_cast
           @attributes.write_from_user(attr_name, value)
diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
index f868f23845..fd569d869a 100644
--- a/activerecord/lib/active_record/attribute_set.rb
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -1,5 +1,5 @@
-require 'active_record/attribute_set/builder'
-require 'active_record/attribute_set/yaml_encoder'
+require "active_record/attribute_set/builder"
+require "active_record/attribute_set/yaml_encoder"
 
 module ActiveRecord
   class AttributeSet # :nodoc:
diff --git a/activerecord/lib/active_record/attribute_set/builder.rb b/activerecord/lib/active_record/attribute_set/builder.rb
index 4ffd39d82d..b4d98ca3c0 100644
--- a/activerecord/lib/active_record/attribute_set/builder.rb
+++ b/activerecord/lib/active_record/attribute_set/builder.rb
@@ -1,4 +1,4 @@
-require 'active_record/attribute'
+require "active_record/attribute"
 
 module ActiveRecord
   class AttributeSet # :nodoc:
diff --git a/activerecord/lib/active_record/attribute_set/yaml_encoder.rb b/activerecord/lib/active_record/attribute_set/yaml_encoder.rb
index f9d527a5a3..52ffe719f4 100644
--- a/activerecord/lib/active_record/attribute_set/yaml_encoder.rb
+++ b/activerecord/lib/active_record/attribute_set/yaml_encoder.rb
@@ -8,7 +8,7 @@ module ActiveRecord
       end
 
       def encode(attribute_set, coder)
-        coder['concise_attributes'] = attribute_set.each_value.map do |attr|
+        coder["concise_attributes"] = attribute_set.each_value.map do |attr|
           if attr.type.equal?(default_types[attr.name])
             attr.with_type(nil)
           else
@@ -18,10 +18,10 @@ module ActiveRecord
       end
 
       def decode(coder)
-        if coder['attributes']
-          coder['attributes']
+        if coder["attributes"]
+          coder["attributes"]
         else
-          attributes_hash = Hash[coder['concise_attributes'].map do |attr|
+          attributes_hash = Hash[coder["concise_attributes"].map do |attr|
             if attr.type.nil?
               attr = attr.with_type(default_types[attr.name])
             end
diff --git a/activerecord/lib/active_record/attributes.rb b/activerecord/lib/active_record/attributes.rb
index ed0302e763..880d9a2b84 100644
--- a/activerecord/lib/active_record/attributes.rb
+++ b/activerecord/lib/active_record/attributes.rb
@@ -1,4 +1,4 @@
-require 'active_record/attribute/user_provided_default'
+require "active_record/attribute/user_provided_default"
 
 module ActiveRecord
   # See ActiveRecord::Attributes::ClassMethods for documentation
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 6a1a27ce41..01d7886406 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1,25 +1,25 @@
-require 'yaml'
-require 'active_support/benchmarkable'
-require 'active_support/dependencies'
-require 'active_support/descendants_tracker'
-require 'active_support/time'
-require 'active_support/core_ext/module/attribute_accessors'
-require 'active_support/core_ext/array/extract_options'
-require 'active_support/core_ext/hash/deep_merge'
-require 'active_support/core_ext/hash/slice'
-require 'active_support/core_ext/hash/transform_values'
-require 'active_support/core_ext/string/behavior'
-require 'active_support/core_ext/kernel/singleton_class'
-require 'active_support/core_ext/module/introspection'
-require 'active_support/core_ext/object/duplicable'
-require 'active_support/core_ext/class/subclasses'
-require 'active_record/attribute_decorators'
-require 'active_record/errors'
-require 'active_record/log_subscriber'
-require 'active_record/explain_subscriber'
-require 'active_record/relation/delegation'
-require 'active_record/attributes'
-require 'active_record/type_caster'
+require "yaml"
+require "active_support/benchmarkable"
+require "active_support/dependencies"
+require "active_support/descendants_tracker"
+require "active_support/time"
+require "active_support/core_ext/module/attribute_accessors"
+require "active_support/core_ext/array/extract_options"
+require "active_support/core_ext/hash/deep_merge"
+require "active_support/core_ext/hash/slice"
+require "active_support/core_ext/hash/transform_values"
+require "active_support/core_ext/string/behavior"
+require "active_support/core_ext/kernel/singleton_class"
+require "active_support/core_ext/module/introspection"
+require "active_support/core_ext/object/duplicable"
+require "active_support/core_ext/class/subclasses"
+require "active_record/attribute_decorators"
+require "active_record/errors"
+require "active_record/log_subscriber"
+require "active_record/explain_subscriber"
+require "active_record/relation/delegation"
+require "active_record/attributes"
+require "active_record/type_caster"
 
 module ActiveRecord #:nodoc:
   # = Active Record
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
index 5ac1e0c001..8b98d9ccd7 100644
--- a/activerecord/lib/active_record/coders/yaml_column.rb
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -1,5 +1,5 @@
-require 'yaml'
-require 'active_support/core_ext/regexp'
+require "yaml"
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module Coders # :nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index 526adc9efe..198a169df2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -1,6 +1,6 @@
-require 'thread'
-require 'concurrent/map'
-require 'monitor'
+require "thread"
+require "concurrent/map"
+require "monitor"
 
 module ActiveRecord
   # Raised when a connection could not be obtained within the connection
@@ -197,7 +197,7 @@ module ActiveRecord
 
             elapsed = Time.now - t0
             if elapsed >= timeout
-              msg = 'could not obtain a connection from the pool within %0.3f seconds (waited %0.3f seconds); all pooled connections were in use' %
+              msg = "could not obtain a connection from the pool within %0.3f seconds (waited %0.3f seconds); all pooled connections were in use" %
                 [timeout, elapsed]
               raise ConnectionTimeoutError, msg
             end
@@ -858,7 +858,7 @@ module ActiveRecord
           payload[:config] = spec.config
         end
 
-        message_bus.instrument('!connection.active_record', payload) do
+        message_bus.instrument("!connection.active_record", payload) do
           owner_to_pool[spec.name] = ConnectionAdapters::ConnectionPool.new(spec)
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index c2d02a6cc2..452e78a40b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -82,7 +82,7 @@ module ActiveRecord
       # Executes +sql+ statement in the context of this connection using
       # +binds+ as the bind substitutes. +name+ is logged along with
       # the executed +sql+ statement.
-      def exec_query(sql, name = 'SQL', binds = [], prepare: false)
+      def exec_query(sql, name = "SQL", binds = [], prepare: false)
         raise NotImplementedError
       end
 
@@ -324,7 +324,7 @@ module ActiveRecord
           end
         end
 
-        execute "INSERT INTO #{quote_table_name(table_name)} (#{key_list.join(', ')}) VALUES (#{value_list.join(', ')})", 'Fixture Insert'
+        execute "INSERT INTO #{quote_table_name(table_name)} (#{key_list.join(', ')}) VALUES (#{value_list.join(', ')})", "Fixture Insert"
       end
 
       def empty_insert_statement_value
@@ -343,8 +343,8 @@ module ActiveRecord
       def sanitize_limit(limit)
         if limit.is_a?(Integer) || limit.is_a?(Arel::Nodes::SqlLiteral)
           limit
-        elsif limit.to_s.include?(',')
-          Arel.sql limit.to_s.split(',').map{ |i| Integer(i) }.join(',')
+        elsif limit.to_s.include?(",")
+          Arel.sql limit.to_s.split(",").map{ |i| Integer(i) }.join(",")
         else
           Integer(limit)
         end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index eda6af08e3..20d009bbf8 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/big_decimal/conversions'
+require "active_support/core_ext/big_decimal/conversions"
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
@@ -116,7 +116,7 @@ module ActiveRecord
       end
 
       def unquoted_true
-        't'.freeze
+        "t".freeze
       end
 
       def quoted_false
@@ -124,7 +124,7 @@ module ActiveRecord
       end
 
       def unquoted_false
-        'f'.freeze
+        "f".freeze
       end
 
       # Quote date/time values for use in SQL input. Includes microseconds
@@ -147,7 +147,7 @@ module ActiveRecord
       end
 
       def quoted_time(value) # :nodoc:
-        quoted_date(value).sub(/\A2000-01-01 /, '')
+        quoted_date(value).sub(/\A2000-01-01 /, "")
       end
 
       private
@@ -168,7 +168,7 @@ module ActiveRecord
         when false      then quoted_false
         when nil        then "NULL"
         # BigDecimals need to be put in a non-normalized form and quoted.
-        when BigDecimal then value.to_s('F')
+        when BigDecimal then value.to_s("F")
         when Numeric, ActiveSupport::Duration then value.to_s
         when Type::Time::Value then "'#{quoted_time(value)}'"
         when Date, Time then "'#{quoted_date(value)}'"
@@ -185,7 +185,7 @@ module ActiveRecord
         when true       then unquoted_true
         when false      then unquoted_false
         # BigDecimals need to be put in a non-normalized form and quoted.
-        when BigDecimal then value.to_s('F')
+        when BigDecimal then value.to_s("F")
         when Type::Time::Value then quoted_time(value)
         when Date, Time then quoted_date(value)
         when *types_which_need_no_typecasting
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index 6add697eeb..322684672f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/strip'
+require "active_support/core_ext/string/strip"
 
 module ActiveRecord
   module ConnectionAdapters
@@ -23,9 +23,9 @@ module ActiveRecord
 
           def visit_AlterTable(o)
             sql = "ALTER TABLE #{quote_table_name(o.name)} "
-            sql << o.adds.map { |col| accept col }.join(' ')
-            sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(' ')
-            sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(' ')
+            sql << o.adds.map { |col| accept col }.join(" ")
+            sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(" ")
+            sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(" ")
           end
 
           def visit_ColumnDefinition(o)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 8dbafc5a4b..c1fc99ce1f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -388,7 +388,7 @@ module ActiveRecord
       end
 
       def aliased_types(name, fallback)
-        'timestamp' == name ? :datetime : fallback
+        "timestamp" == name ? :datetime : fallback
       end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
index 677a4c6bd0..321e08c5ca 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
@@ -40,7 +40,7 @@ module ActiveRecord
         default = schema_default(column) if column.has_default?
         spec[:default]   = default unless default.nil?
 
-        spec[:null] = 'false' unless column.null
+        spec[:null] = "false" unless column.null
 
         if collation = schema_collation(column)
           spec[:collation] = collation
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 19c265db6e..77e97a6d1b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -1,6 +1,6 @@
-require 'active_record/migration/join_table'
-require 'active_support/core_ext/string/access'
-require 'digest'
+require "active_record/migration/join_table"
+require "active_support/core_ext/string/access"
+require "digest"
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
@@ -25,7 +25,7 @@ module ActiveRecord
 
       # Truncates a table alias according to the limits of the current adapter.
       def table_alias_for(table_name)
-        table_name[0...table_alias_length].tr('.', '_')
+        table_name[0...table_alias_length].tr(".", "_")
       end
 
       # Returns the relation names useable to back Active Record models.
@@ -985,7 +985,7 @@ module ActiveRecord
       end
 
       def dump_schema_information #:nodoc:
-        versions = ActiveRecord::SchemaMigration.order('version').pluck(:version)
+        versions = ActiveRecord::SchemaMigration.order("version").pluck(:version)
         insert_versions_sql(versions)
       end
 
@@ -1026,7 +1026,7 @@ module ActiveRecord
         migrated = select_values("SELECT version FROM #{sm_table}").map(&:to_i)
         paths = migrations_paths.map {|p| "#{p}/[0-9]*_*.rb" }
         versions = Dir[*paths].map do |filename|
-          filename.split('/').last.split('_').first.to_i
+          filename.split("/").last.split("_").first.to_i
         end
 
         unless migrated.include?(version)
@@ -1178,7 +1178,7 @@ module ActiveRecord
         def quoted_columns_for_index(column_names, options = {})
           return [column_names] if column_names.is_a?(String)
 
-          option_strings = Hash[column_names.map {|name| [name, '']}]
+          option_strings = Hash[column_names.map {|name| [name, ""]}]
 
           # add index sort order if supported
           if supports_index_sort_order?
@@ -1205,7 +1205,7 @@ module ActiveRecord
           end
 
           if column_names.any?
-            checks << lambda { |i| i.columns.join('_and_') == column_names.join('_and_') }
+            checks << lambda { |i| i.columns.join("_and_") == column_names.join("_and_") }
           end
 
           raise ArgumentError "No name or columns specified" if checks.none?
@@ -1255,7 +1255,7 @@ module ActiveRecord
 
       def index_name_options(column_names) # :nodoc:
         if column_names.is_a?(String)
-          column_names = column_names.scan(/\w+/).join('_')
+          column_names = column_names.scan(/\w+/).join("_")
         end
 
         { column: column_names }
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
index ca795cb1ad..d6b03e1eb1 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/transaction.rb
@@ -195,7 +195,7 @@ module ActiveRecord
         raise
       ensure
         unless error
-          if Thread.current.status == 'aborting'
+          if Thread.current.status == "aborting"
             rollback_transaction if transaction
           else
             begin
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 0b8bacff4e..7ba3b5f43b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -1,11 +1,11 @@
-require 'active_record/type'
-require 'active_record/connection_adapters/determine_if_preparable_visitor'
-require 'active_record/connection_adapters/schema_cache'
-require 'active_record/connection_adapters/sql_type_metadata'
-require 'active_record/connection_adapters/abstract/schema_dumper'
-require 'active_record/connection_adapters/abstract/schema_creation'
-require 'arel/collectors/bind'
-require 'arel/collectors/sql_string'
+require "active_record/type"
+require "active_record/connection_adapters/determine_if_preparable_visitor"
+require "active_record/connection_adapters/schema_cache"
+require "active_record/connection_adapters/sql_type_metadata"
+require "active_record/connection_adapters/abstract/schema_dumper"
+require "active_record/connection_adapters/abstract/schema_creation"
+require "arel/collectors/bind"
+require "arel/collectors/sql_string"
 
 module ActiveRecord
   module ConnectionAdapters # :nodoc:
@@ -14,7 +14,7 @@ module ActiveRecord
     autoload :Column
     autoload :ConnectionSpecification
 
-    autoload_at 'active_record/connection_adapters/abstract/schema_definitions' do
+    autoload_at "active_record/connection_adapters/abstract/schema_definitions" do
       autoload :IndexDefinition
       autoload :ColumnDefinition
       autoload :ChangeColumnDefinition
@@ -25,11 +25,11 @@ module ActiveRecord
       autoload :ReferenceDefinition
     end
 
-    autoload_at 'active_record/connection_adapters/abstract/connection_pool' do
+    autoload_at "active_record/connection_adapters/abstract/connection_pool" do
       autoload :ConnectionHandler
     end
 
-    autoload_under 'abstract' do
+    autoload_under "abstract" do
       autoload :SchemaStatements
       autoload :DatabaseStatements
       autoload :DatabaseLimits
@@ -39,7 +39,7 @@ module ActiveRecord
       autoload :Savepoints
     end
 
-    autoload_at 'active_record/connection_adapters/abstract/transaction' do
+    autoload_at "active_record/connection_adapters/abstract/transaction" do
       autoload :TransactionManager
       autoload :NullTransaction
       autoload :RealTransaction
@@ -61,7 +61,7 @@ module ActiveRecord
     # Most of the methods in the adapter are useful during migrations. Most
     # notably, the instance methods provided by SchemaStatements are very useful.
     class AbstractAdapter
-      ADAPTER_NAME = 'Abstract'.freeze
+      ADAPTER_NAME = "Abstract".freeze
       include Quoting, DatabaseStatements, SchemaStatements
       include DatabaseLimits
       include QueryCache
@@ -120,11 +120,11 @@ module ActiveRecord
         include Comparable
 
         def initialize(version_string)
-          @version = version_string.split('.').map(&:to_i)
+          @version = version_string.split(".").map(&:to_i)
         end
 
         def <=>(version_string)
-          @version <=> version_string.split('.').map(&:to_i)
+          @version <=> version_string.split(".").map(&:to_i)
         end
       end
 
@@ -164,9 +164,9 @@ module ActiveRecord
       # this method must only be called while holding connection pool's mutex
       def lease
         if in_use?
-          msg = 'Cannot lease connection, '
+          msg = "Cannot lease connection, "
           if @owner == Thread.current
-            msg << 'it is already leased by the current thread.'
+            msg << "it is already leased by the current thread."
           else
             msg << "it is already in use by a different thread: #{@owner}. " <<
                    "Current thread: #{Thread.current}."
@@ -193,7 +193,7 @@ module ActiveRecord
 
           @owner = nil
         else
-          raise ActiveRecordError, 'Cannot expire connection, it is not currently leased.'
+          raise ActiveRecordError, "Cannot expire connection, it is not currently leased."
         end
       end
 
@@ -206,7 +206,7 @@ module ActiveRecord
             @owner = Thread.current
           end
         else
-          raise ActiveRecordError, 'Cannot steal connection, it is not currently leased.'
+          raise ActiveRecordError, "Cannot steal connection, it is not currently leased."
         end
       end
 
@@ -508,12 +508,12 @@ module ActiveRecord
         register_class_with_limit m, %r(float)i,         Type::Float
         register_class_with_limit m, %r(int)i,           Type::Integer
 
-        m.alias_type %r(blob)i,      'binary'
-        m.alias_type %r(clob)i,      'text'
-        m.alias_type %r(timestamp)i, 'datetime'
-        m.alias_type %r(numeric)i,   'decimal'
-        m.alias_type %r(number)i,    'decimal'
-        m.alias_type %r(double)i,    'float'
+        m.alias_type %r(blob)i,      "binary"
+        m.alias_type %r(clob)i,      "text"
+        m.alias_type %r(timestamp)i, "datetime"
+        m.alias_type %r(numeric)i,   "decimal"
+        m.alias_type %r(number)i,    "decimal"
+        m.alias_type %r(double)i,    "float"
 
         m.register_type(%r(decimal)i) do |sql_type|
           scale = extract_scale(sql_type)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 5e9705e02f..ee86e6e128 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -1,15 +1,15 @@
-require 'active_record/connection_adapters/abstract_adapter'
-require 'active_record/connection_adapters/statement_pool'
-require 'active_record/connection_adapters/mysql/column'
-require 'active_record/connection_adapters/mysql/explain_pretty_printer'
-require 'active_record/connection_adapters/mysql/quoting'
-require 'active_record/connection_adapters/mysql/schema_creation'
-require 'active_record/connection_adapters/mysql/schema_definitions'
-require 'active_record/connection_adapters/mysql/schema_dumper'
-require 'active_record/connection_adapters/mysql/type_metadata'
-
-require 'active_support/core_ext/string/strip'
-require 'active_support/core_ext/regexp'
+require "active_record/connection_adapters/abstract_adapter"
+require "active_record/connection_adapters/statement_pool"
+require "active_record/connection_adapters/mysql/column"
+require "active_record/connection_adapters/mysql/explain_pretty_printer"
+require "active_record/connection_adapters/mysql/quoting"
+require "active_record/connection_adapters/mysql/schema_creation"
+require "active_record/connection_adapters/mysql/schema_definitions"
+require "active_record/connection_adapters/mysql/schema_dumper"
+require "active_record/connection_adapters/mysql/type_metadata"
+
+require "active_support/core_ext/string/strip"
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module ConnectionAdapters
@@ -68,16 +68,16 @@ module ActiveRecord
 
         @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))
 
-        if version < '5.0.0'
+        if version < "5.0.0"
           raise "Your version of MySQL (#{full_version.match(/^\d+\.\d+\.\d+/)[0]}) is too old. Active Record supports MySQL >= 5.0."
         end
       end
 
-      CHARSETS_OF_4BYTES_MAXLEN = ['utf8mb4', 'utf16', 'utf16le', 'utf32']
+      CHARSETS_OF_4BYTES_MAXLEN = ["utf8mb4", "utf16", "utf16le", "utf32"]
 
       def internal_string_options_for_primary_key # :nodoc:
         super.tap { |options|
-          options[:collation] = collation.sub(/\A[^_]+/, 'utf8') if CHARSETS_OF_4BYTES_MAXLEN.include?(charset)
+          options[:collation] = collation.sub(/\A[^_]+/, "utf8") if CHARSETS_OF_4BYTES_MAXLEN.include?(charset)
         }
       end
 
@@ -136,9 +136,9 @@ module ActiveRecord
 
       def supports_datetime_with_precision?
         if mariadb?
-          version >= '5.3.0'
+          version >= "5.3.0"
         else
-          version >= '5.6.4'
+          version >= "5.6.4"
         end
       end
 
@@ -159,7 +159,7 @@ module ActiveRecord
       end
 
       def index_algorithms
-        { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
+        { default: "ALGORITHM = DEFAULT", copy: "ALGORITHM = COPY", inplace: "ALGORITHM = INPLACE" }
       end
 
       # HELPER METHODS ===========================================
@@ -208,7 +208,7 @@ module ActiveRecord
       def explain(arel, binds = [])
         sql     = "EXPLAIN #{to_sql(arel, binds)}"
         start   = Time.now
-        result  = exec_query(sql, 'EXPLAIN', binds)
+        result  = exec_query(sql, "EXPLAIN", binds)
         elapsed = Time.now - start
 
         MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
@@ -294,17 +294,17 @@ module ActiveRecord
       end
 
       def current_database
-        select_value 'SELECT DATABASE() as db'
+        select_value "SELECT DATABASE() as db"
       end
 
       # Returns the database character set.
       def charset
-        show_variable 'character_set_database'
+        show_variable "character_set_database"
       end
 
       # Returns the database collation strategy.
       def collation
-        show_variable 'collation_database'
+        show_variable "collation_database"
       end
 
       def tables(name = nil) # :nodoc:
@@ -327,7 +327,7 @@ module ActiveRecord
         sql = "SELECT table_name FROM information_schema.tables "
         sql << "WHERE table_schema = #{quote(@config[:database])}"
 
-        select_values(sql, 'SCHEMA')
+        select_values(sql, "SCHEMA")
       end
 
       def truncate(table_name, name = nil)
@@ -353,11 +353,11 @@ module ActiveRecord
         sql = "SELECT table_name FROM information_schema.tables "
         sql << "WHERE table_schema = #{quote(schema)} AND table_name = #{quote(name)}"
 
-        select_values(sql, 'SCHEMA').any?
+        select_values(sql, "SCHEMA").any?
       end
 
       def views # :nodoc:
-        select_values("SHOW FULL TABLES WHERE table_type = 'VIEW'", 'SCHEMA')
+        select_values("SHOW FULL TABLES WHERE table_type = 'VIEW'", "SCHEMA")
       end
 
       def view_exists?(view_name) # :nodoc:
@@ -368,17 +368,17 @@ module ActiveRecord
         sql = "SELECT table_name FROM information_schema.tables WHERE table_type = 'VIEW'"
         sql << " AND table_schema = #{quote(schema)} AND table_name = #{quote(name)}"
 
-        select_values(sql, 'SCHEMA').any?
+        select_values(sql, "SCHEMA").any?
       end
 
       # Returns an array of indexes for the given table.
       def indexes(table_name, name = nil) #:nodoc:
         indexes = []
         current_index = nil
-        execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
+        execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", "SCHEMA") do |result|
           each_hash(result) do |row|
             if current_index != row[:Key_name]
-              next if row[:Key_name] == 'PRIMARY' # skip the primary key
+              next if row[:Key_name] == "PRIMARY" # skip the primary key
               current_index = row[:Key_name]
 
               mysql_index_type = row[:Index_type].downcase.to_sym
@@ -412,7 +412,7 @@ module ActiveRecord
       def table_comment(table_name) # :nodoc:
         schema, name = extract_schema_qualified_name(table_name)
 
-        select_value(<<-SQL.strip_heredoc, 'SCHEMA')
+        select_value(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT table_comment
           FROM information_schema.tables
           WHERE table_schema = #{quote(schema)}
@@ -421,7 +421,7 @@ module ActiveRecord
       end
 
       def create_table(table_name, **options) #:nodoc:
-        super(table_name, options: 'ENGINE=InnoDB', **options)
+        super(table_name, options: "ENGINE=InnoDB", **options)
       end
 
       def bulk_change_table(table_name, operations) #:nodoc:
@@ -518,7 +518,7 @@ module ActiveRecord
 
         schema, name = extract_schema_qualified_name(table_name)
 
-        fk_info = select_all(<<-SQL.strip_heredoc, 'SCHEMA')
+        fk_info = select_all(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT fk.referenced_table_name AS 'to_table',
                  fk.referenced_column_name AS 'primary_key',
                  fk.column_name AS 'column',
@@ -535,15 +535,15 @@ module ActiveRecord
 
         fk_info.map do |row|
           options = {
-            column: row['column'],
-            name: row['name'],
-            primary_key: row['primary_key']
+            column: row["column"],
+            name: row["name"],
+            primary_key: row["primary_key"]
           }
 
-          options[:on_update] = extract_foreign_key_action(row['on_update'])
-          options[:on_delete] = extract_foreign_key_action(row['on_delete'])
+          options[:on_update] = extract_foreign_key_action(row["on_update"])
+          options[:on_delete] = extract_foreign_key_action(row["on_delete"])
 
-          ForeignKeyDefinition.new(table_name, row['to_table'], options)
+          ForeignKeyDefinition.new(table_name, row["to_table"], options)
         end
       end
 
@@ -553,7 +553,7 @@ module ActiveRecord
         create_table_info = create_table_info(table_name)
 
         # strip create_definitions and partition_options
-        raw_table_options = create_table_info.sub(/\A.*\n\) /m, '').sub(/\n\/\*!.*\*\/\n\z/m, '').strip
+        raw_table_options = create_table_info.sub(/\A.*\n\) /m, "").sub(/\n\/\*!.*\*\/\n\z/m, "").strip
 
         # strip AUTO_INCREMENT
         raw_table_options.sub!(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')
@@ -561,7 +561,7 @@ module ActiveRecord
         table_options[:options] = raw_table_options
 
         # strip COMMENT
-        if raw_table_options.sub!(/ COMMENT='.+'/, '')
+        if raw_table_options.sub!(/ COMMENT='.+'/, "")
           table_options[:comment] = table_comment(table_name)
         end
 
@@ -571,13 +571,13 @@ module ActiveRecord
       # Maps logical Rails types to MySQL-specific data types.
       def type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil)
         sql = case type.to_s
-        when 'integer'
+        when "integer"
           integer_to_sql(limit)
-        when 'text'
+        when "text"
           text_to_sql(limit)
-        when 'blob'
+        when "blob"
           binary_to_sql(limit)
-        when 'binary'
+        when "binary"
           if (0..0xfff) === limit
             "varbinary(#{limit})"
           else
@@ -587,13 +587,13 @@ module ActiveRecord
           super(type, limit, precision, scale)
         end
 
-        sql << ' unsigned' if unsigned && type != :primary_key
+        sql << " unsigned" if unsigned && type != :primary_key
         sql
       end
 
       # SHOW VARIABLES LIKE 'name'
       def show_variable(name)
-        select_value("SELECT @@#{name}", 'SCHEMA')
+        select_value("SELECT @@#{name}", "SCHEMA")
       rescue ActiveRecord::StatementInvalid
         nil
       end
@@ -603,7 +603,7 @@ module ActiveRecord
 
         schema, name = extract_schema_qualified_name(table_name)
 
-        select_values(<<-SQL.strip_heredoc, 'SCHEMA')
+        select_values(<<-SQL.strip_heredoc, "SCHEMA")
           SELECT column_name
           FROM information_schema.key_column_usage
           WHERE constraint_name = 'PRIMARY'
@@ -635,10 +635,10 @@ module ActiveRecord
           # Convert Arel node to string
           s = s.to_sql unless s.is_a?(String)
           # Remove any ASC/DESC modifiers
-          s.gsub(/\s+(?:ASC|DESC)\b/i, '')
+          s.gsub(/\s+(?:ASC|DESC)\b/i, "")
         }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
-        [super, *order_columns].join(', ')
+        [super, *order_columns].join(", ")
       end
 
       def strict_mode?
@@ -675,18 +675,18 @@ module ActiveRecord
         register_integer_type m, %r(^tinyint)i,   limit: 1
 
         m.register_type %r(^tinyint\(1\))i, Type::Boolean.new if emulate_booleans
-        m.alias_type %r(year)i,          'integer'
-        m.alias_type %r(bit)i,           'binary'
+        m.alias_type %r(year)i,          "integer"
+        m.alias_type %r(bit)i,           "binary"
 
         m.register_type(%r(enum)i) do |sql_type|
           limit = sql_type[/^enum\((.+)\)/i, 1]
-            .split(',').map{|enum| enum.strip.length - 2}.max
+            .split(",").map{|enum| enum.strip.length - 2}.max
           MysqlString.new(limit: limit)
         end
 
         m.register_type(%r(^set)i) do |sql_type|
           limit = sql_type[/^set\((.+)\)/i, 1]
-            .split(',').map{|set| set.strip.length - 1}.sum - 1
+            .split(",").map{|set| set.strip.length - 1}.sum - 1
           MysqlString.new(limit: limit)
         end
       end
@@ -727,7 +727,7 @@ module ActiveRecord
       end
 
       def quoted_columns_for_index(column_names, options = {})
-        option_strings = Hash[column_names.map {|name| [name, '']}]
+        option_strings = Hash[column_names.map {|name| [name, ""]}]
 
         # add index length
         option_strings = add_index_length(option_strings, column_names, options)
@@ -789,7 +789,7 @@ module ActiveRecord
           auto_increment: column.auto_increment?
         }
 
-        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
+        current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", "SCHEMA")["Type"]
         td = create_table_definition(table_name)
         cd = td.new_column_definition(new_column_name, current_type, options)
         schema_creation.accept(ChangeColumnDefinition.new(cd, column.name))
@@ -836,30 +836,30 @@ module ActiveRecord
 
         subselect = Arel::SelectManager.new(select.engine)
         subselect.project Arel.sql(key.name)
-        subselect.from subsubselect.as('__active_record_temp')
+        subselect.from subsubselect.as("__active_record_temp")
       end
 
       def supports_rename_index?
-        mariadb? ? false : version >= '5.7.6'
+        mariadb? ? false : version >= "5.7.6"
       end
 
       def configure_connection
         variables = @config.fetch(:variables, {}).stringify_keys
 
         # By default, MySQL 'where id is null' selects the last inserted id; Turn this off.
-        variables['sql_auto_is_null'] = 0
+        variables["sql_auto_is_null"] = 0
 
         # Increase timeout so the server doesn't disconnect us.
         wait_timeout = @config[:wait_timeout]
         wait_timeout = 2147483 unless wait_timeout.is_a?(Integer)
-        variables['wait_timeout'] = self.class.type_cast_config_to_integer(wait_timeout)
+        variables["wait_timeout"] = self.class.type_cast_config_to_integer(wait_timeout)
 
-        defaults = [':default', :default].to_set
+        defaults = [":default", :default].to_set
 
         # Make MySQL reject illegal values rather than truncating or blanking them, see
         # http://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sqlmode_strict_all_tables
         # If the user has provided another value for sql_mode, don't replace it.
-        if sql_mode = variables.delete('sql_mode')
+        if sql_mode = variables.delete("sql_mode")
           sql_mode = quote(sql_mode)
         elsif !defaults.include?(strict_mode?)
           if strict_mode?
@@ -890,22 +890,22 @@ module ActiveRecord
             "@@SESSION.#{k} = #{quote(v)}"
           end
           # or else nil; compact to clear nils out
-        end.compact.join(', ')
+        end.compact.join(", ")
 
         # ...and send them all in one query
         @connection.query  "SET #{encoding} #{sql_mode_assignment} #{variable_assignments}"
       end
 
       def column_definitions(table_name) # :nodoc:
-        execute_and_free("SHOW FULL FIELDS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
+        execute_and_free("SHOW FULL FIELDS FROM #{quote_table_name(table_name)}", "SCHEMA") do |result|
           each_hash(result)
         end
       end
 
       def extract_foreign_key_action(specifier) # :nodoc:
         case specifier
-        when 'CASCADE'; :cascade
-        when 'SET NULL'; :nullify
+        when "CASCADE"; :cascade
+        when "SET NULL"; :nullify
         end
       end
 
@@ -925,31 +925,31 @@ module ActiveRecord
 
       def integer_to_sql(limit) # :nodoc:
         case limit
-        when 1; 'tinyint'
-        when 2; 'smallint'
-        when 3; 'mediumint'
-        when nil, 4; 'int'
-        when 5..8; 'bigint'
+        when 1; "tinyint"
+        when 2; "smallint"
+        when 3; "mediumint"
+        when nil, 4; "int"
+        when 5..8; "bigint"
         else raise(ActiveRecordError, "No integer type has byte size #{limit}")
         end
       end
 
       def text_to_sql(limit) # :nodoc:
         case limit
-        when 0..0xff;               'tinytext'
-        when nil, 0x100..0xffff;    'text'
-        when 0x10000..0xffffff;     'mediumtext'
-        when 0x1000000..0xffffffff; 'longtext'
+        when 0..0xff;               "tinytext"
+        when nil, 0x100..0xffff;    "text"
+        when 0x10000..0xffffff;     "mediumtext"
+        when 0x1000000..0xffffffff; "longtext"
         else raise(ActiveRecordError, "No text type has byte length #{limit}")
         end
       end
 
       def binary_to_sql(limit) # :nodoc:
         case limit
-        when 0..0xff;               'tinyblob'
-        when nil, 0x100..0xffff;    'blob'
-        when 0x10000..0xffffff;     'mediumblob'
-        when 0x1000000..0xffffffff; 'longblob'
+        when 0..0xff;               "tinyblob"
+        when nil, 0x100..0xffff;    "blob"
+        when 0x10000..0xffffff;     "mediumblob"
+        when 0x1000000..0xffffffff; "longblob"
         else raise(ActiveRecordError, "No binary type has byte length #{limit}")
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
index 346916337e..dbb0a95444 100644
--- a/activerecord/lib/active_record/connection_adapters/connection_specification.rb
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -1,4 +1,4 @@
-require 'uri'
+require "uri"
 
 module ActiveRecord
   module ConnectionAdapters
@@ -37,11 +37,11 @@ module ActiveRecord
         def initialize(url)
           raise "Database URL cannot be empty" if url.blank?
           @uri     = uri_parser.parse(url)
-          @adapter = @uri.scheme && @uri.scheme.tr('-', '_')
+          @adapter = @uri.scheme && @uri.scheme.tr("-", "_")
           @adapter = "postgresql" if @adapter == "postgres"
 
           if @uri.opaque
-            @uri.opaque, @query = @uri.opaque.split('?', 2)
+            @uri.opaque, @query = @uri.opaque.split("?", 2)
           else
             @query = @uri.query
           end
@@ -74,7 +74,7 @@ module ActiveRecord
         #   "localhost"
         #   # => {}
         def query_hash
-          Hash[(@query || '').split("&").map { |pair| pair.split("=") }]
+          Hash[(@query || "").split("&").map { |pair| pair.split("=") }]
         end
 
         def raw_config
@@ -95,7 +95,7 @@ module ActiveRecord
 
         # Returns name of the database.
         def database_from_path
-          if @adapter == 'sqlite3'
+          if @adapter == "sqlite3"
             # 'sqlite3:/foo' is absolute, because that makes sense. The
             # corresponding relative version, 'sqlite3:foo', is handled
             # elsewhere, as an "opaque".
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/column.rb b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
index ea554b188c..cb068a61c7 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/column.rb
@@ -27,14 +27,14 @@ module ActiveRecord
         end
 
         def auto_increment?
-          extra == 'auto_increment'
+          extra == "auto_increment"
         end
 
         private
 
         def extract_default
           if blob_or_text_column?
-            @default = null || strict ? nil : ''
+            @default = null || strict ? nil : ""
           end
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
index fb0eda753f..cd606d11a7 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb
@@ -33,7 +33,7 @@ module ActiveRecord
           super
         end
 
-        def exec_query(sql, name = 'SQL', binds = [], prepare: false)
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
           if without_prepared_statement?(binds)
             execute_and_free(sql, name) do |result|
               ActiveRecord::Result.new(result.fields, result.to_a) if result
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb
index 1820853196..5a6b33cb04 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/explain_pretty_printer.rb
@@ -39,7 +39,7 @@ module ActiveRecord
         def compute_column_widths(result)
           [].tap do |widths|
             result.columns.each_with_index do |column, i|
-              cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? 'NULL' : r[i].to_s}
+              cells_in_column = [column] + result.rows.map {|r| r[i].nil? ? "NULL" : r[i].to_s}
               widths << cells_in_column.map(&:length).max
             end
           end
@@ -47,21 +47,21 @@ module ActiveRecord
 
         def build_separator(widths)
           padding = 1
-          '+' + widths.map {|w| '-' * (w + (padding*2))}.join('+') + '+'
+          "+" + widths.map {|w| "-" * (w + (padding*2))}.join("+") + "+"
         end
 
         def build_cells(items, widths)
           cells = []
           items.each_with_index do |item, i|
-            item = 'NULL' if item.nil?
-            justifier = item.is_a?(Numeric) ? 'rjust' : 'ljust'
+            item = "NULL" if item.nil?
+            justifier = item.is_a?(Numeric) ? "rjust" : "ljust"
             cells << item.to_s.send(justifier, widths[i])
           end
-          '| ' + cells.join(' | ') + ' |'
+          "| " + cells.join(" | ") + " |"
         end
 
         def build_footer(nrows, elapsed)
-          rows_label = nrows == 1 ? 'row' : 'rows'
+          rows_label = nrows == 1 ? "row" : "rows"
           "#{nrows} #{rows_label} in set (%.2f sec)" % elapsed
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb b/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb
index af1db30047..381787868b 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/quoting.rb
@@ -2,14 +2,14 @@ module ActiveRecord
   module ConnectionAdapters
     module MySQL
       module Quoting # :nodoc:
-        QUOTED_TRUE, QUOTED_FALSE = '1'.freeze, '0'.freeze
+        QUOTED_TRUE, QUOTED_FALSE = "1".freeze, "0".freeze
 
         def quote_column_name(name)
           @quoted_column_names[name] ||= "`#{super.gsub('`', '``')}`".freeze
         end
 
         def quote_table_name(name)
-          @quoted_table_names[name] ||= super.gsub('.', '`.`').freeze
+          @quoted_table_names[name] ||= super.gsub(".", "`.`").freeze
         end
 
         def quoted_true
@@ -32,7 +32,7 @@ module ActiveRecord
           if supports_datetime_with_precision?
             super
           else
-            super.sub(/\.\d{6}\z/, '')
+            super.sub(/\.\d{6}\z/, "")
           end
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
index 2ba9657f24..3e644f386f 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_dumper.rb
@@ -5,17 +5,17 @@ module ActiveRecord
         def column_spec_for_primary_key(column)
           if column.bigint?
             spec = { id: :bigint.inspect }
-            spec[:default] = schema_default(column) || 'nil' unless column.auto_increment?
+            spec[:default] = schema_default(column) || "nil" unless column.auto_increment?
           else
             spec = super
           end
-          spec[:unsigned] = 'true' if column.unsigned?
+          spec[:unsigned] = "true" if column.unsigned?
           spec
         end
 
         def prepare_column_options(column)
           spec = super
-          spec[:unsigned] = 'true' if column.unsigned?
+          spec[:unsigned] = "true" if column.unsigned?
           spec
         end
 
@@ -30,7 +30,7 @@ module ActiveRecord
         end
 
         def schema_type(column)
-          if column.sql_type == 'tinyblob'
+          if column.sql_type == "tinyblob"
             :blob
           else
             super
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
index 22d35f1db5..cace451df2 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -1,9 +1,9 @@
-require 'active_record/connection_adapters/abstract_mysql_adapter'
-require 'active_record/connection_adapters/mysql/database_statements'
+require "active_record/connection_adapters/abstract_mysql_adapter"
+require "active_record/connection_adapters/mysql/database_statements"
 
-gem 'mysql2', '>= 0.3.18', '< 0.5'
-require 'mysql2'
-raise 'mysql2 0.4.3 is not supported. Please upgrade to 0.4.4+' if Mysql2::VERSION == '0.4.3'
+gem "mysql2", ">= 0.3.18", "< 0.5"
+require "mysql2"
+raise "mysql2 0.4.3 is not supported. Please upgrade to 0.4.4+" if Mysql2::VERSION == "0.4.3"
 
 module ActiveRecord
   module ConnectionHandling # :nodoc:
@@ -11,7 +11,7 @@ module ActiveRecord
     def mysql2_connection(config)
       config = config.symbolize_keys
 
-      config[:username] = 'root' if config[:username].nil?
+      config[:username] = "root" if config[:username].nil?
       config[:flags] ||= 0
 
       if Mysql2::Client.const_defined? :FOUND_ROWS
@@ -35,7 +35,7 @@ module ActiveRecord
 
   module ConnectionAdapters
     class Mysql2Adapter < AbstractMysqlAdapter
-      ADAPTER_NAME = 'Mysql2'.freeze
+      ADAPTER_NAME = "Mysql2".freeze
 
       include MySQL::DatabaseStatements
 
@@ -46,7 +46,7 @@ module ActiveRecord
       end
 
       def supports_json?
-        !mariadb? && version >= '5.7.8'
+        !mariadb? && version >= "5.7.8"
       end
 
       def supports_comments?
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
index da533463bf..b5a3340c18 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -4,7 +4,7 @@ module ActiveRecord
       module DatabaseStatements
         def explain(arel, binds = [])
           sql = "EXPLAIN #{to_sql(arel, binds)}"
-          PostgreSQL::ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds))
+          PostgreSQL::ExplainPrettyPrinter.new.pp(exec_query(sql, "EXPLAIN", binds))
         end
 
         def select_value(arel, name = nil, binds = [])
@@ -74,9 +74,9 @@ module ActiveRecord
               #  (2) $12.345.678,12
               case data
               when /^-?\D+[\d,]+\.\d{2}$/  # (1)
-                data.gsub!(/[^-\d.]/, '')
+                data.gsub!(/[^-\d.]/, "")
               when /^-?\D+[\d.]+,\d{2}$/  # (2)
-                data.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
+                data.gsub!(/[^-\d,]/, "").sub!(/,/, ".")
               end
             end
           end
@@ -99,7 +99,7 @@ module ActiveRecord
           end
         end
 
-        def exec_query(sql, name = 'SQL', binds = [], prepare: false)
+        def exec_query(sql, name = "SQL", binds = [], prepare: false)
           execute_and_clear(sql, name, binds, prepare: prepare) do |result|
             types = {}
             fields = result.fields
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb
index 789b88912c..f95a63968c 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/explain_pretty_printer.rb
@@ -26,12 +26,12 @@ module ActiveRecord
           pp = []
 
           pp << header.center(width).rstrip
-          pp << '-' * width
+          pp << "-" * width
 
           pp += lines.map {|line| " #{line}"}
 
           nrows = result.rows.length
-          rows_label = nrows == 1 ? 'row' : 'rows'
+          rows_label = nrows == 1 ? "row" : "rows"
           pp << "(#{nrows} #{rows_label})"
 
           pp.join("\n") + "\n"
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
index 68752cdd80..8c318886cf 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -1,25 +1,25 @@
-require 'active_record/connection_adapters/postgresql/oid/array'
-require 'active_record/connection_adapters/postgresql/oid/bit'
-require 'active_record/connection_adapters/postgresql/oid/bit_varying'
-require 'active_record/connection_adapters/postgresql/oid/bytea'
-require 'active_record/connection_adapters/postgresql/oid/cidr'
-require 'active_record/connection_adapters/postgresql/oid/date_time'
-require 'active_record/connection_adapters/postgresql/oid/decimal'
-require 'active_record/connection_adapters/postgresql/oid/enum'
-require 'active_record/connection_adapters/postgresql/oid/hstore'
-require 'active_record/connection_adapters/postgresql/oid/inet'
-require 'active_record/connection_adapters/postgresql/oid/json'
-require 'active_record/connection_adapters/postgresql/oid/jsonb'
-require 'active_record/connection_adapters/postgresql/oid/money'
-require 'active_record/connection_adapters/postgresql/oid/point'
-require 'active_record/connection_adapters/postgresql/oid/rails_5_1_point'
-require 'active_record/connection_adapters/postgresql/oid/range'
-require 'active_record/connection_adapters/postgresql/oid/specialized_string'
-require 'active_record/connection_adapters/postgresql/oid/uuid'
-require 'active_record/connection_adapters/postgresql/oid/vector'
-require 'active_record/connection_adapters/postgresql/oid/xml'
+require "active_record/connection_adapters/postgresql/oid/array"
+require "active_record/connection_adapters/postgresql/oid/bit"
+require "active_record/connection_adapters/postgresql/oid/bit_varying"
+require "active_record/connection_adapters/postgresql/oid/bytea"
+require "active_record/connection_adapters/postgresql/oid/cidr"
+require "active_record/connection_adapters/postgresql/oid/date_time"
+require "active_record/connection_adapters/postgresql/oid/decimal"
+require "active_record/connection_adapters/postgresql/oid/enum"
+require "active_record/connection_adapters/postgresql/oid/hstore"
+require "active_record/connection_adapters/postgresql/oid/inet"
+require "active_record/connection_adapters/postgresql/oid/json"
+require "active_record/connection_adapters/postgresql/oid/jsonb"
+require "active_record/connection_adapters/postgresql/oid/money"
+require "active_record/connection_adapters/postgresql/oid/point"
+require "active_record/connection_adapters/postgresql/oid/rails_5_1_point"
+require "active_record/connection_adapters/postgresql/oid/range"
+require "active_record/connection_adapters/postgresql/oid/specialized_string"
+require "active_record/connection_adapters/postgresql/oid/uuid"
+require "active_record/connection_adapters/postgresql/oid/vector"
+require "active_record/connection_adapters/postgresql/oid/xml"
 
-require 'active_record/connection_adapters/postgresql/oid/type_map_initializer'
+require "active_record/connection_adapters/postgresql/oid/type_map_initializer"
 
 module ActiveRecord
   module ConnectionAdapters
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
index 87593ef704..9e0e6732c3 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/array.rb
@@ -8,7 +8,7 @@ module ActiveRecord
           attr_reader :subtype, :delimiter
           delegate :type, :user_input_in_time_zone, :limit, to: :subtype
 
-          def initialize(subtype, delimiter = ',')
+          def initialize(subtype, delimiter = ",")
             @subtype = subtype
             @delimiter = delimiter
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
index 838cb63281..5225609e37 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/cidr.rb
@@ -1,4 +1,4 @@
-require 'ipaddr'
+require "ipaddr"
 
 module ActiveRecord
   module ConnectionAdapters
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
index 424769f765..b7acbf7178 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb
@@ -5,8 +5,8 @@ module ActiveRecord
         class DateTime < Type::DateTime # :nodoc:
           def cast_value(value)
             case value
-            when 'infinity' then ::Float::INFINITY
-            when '-infinity' then -::Float::INFINITY
+            when "infinity" then ::Float::INFINITY
+            when "-infinity" then -::Float::INFINITY
             when / BC$/
               astronomical_year = format("%04d", -value[/^\d+/].to_i + 1)
               super(value.sub(/ BC$/, "").sub(/^\d+/, astronomical_year))
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
index 9270fc9f21..2e55a5f8b8 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -12,7 +12,7 @@ module ActiveRecord
           def deserialize(value)
             if value.is_a?(::String)
               ::Hash[value.scan(HstorePair).map { |k, v|
-                v = v.upcase == 'NULL' ? nil : v.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
+                v = v.upcase == "NULL" ? nil : v.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
                 k = k.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
                 [k, v]
               }]
@@ -23,7 +23,7 @@ module ActiveRecord
 
           def serialize(value)
             if value.is_a?(::Hash)
-              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(', ')
+              value.map { |k, v| "#{escape_hstore(k)}=>#{escape_hstore(v)}" }.join(", ")
             else
               value
             end
@@ -43,7 +43,7 @@ module ActiveRecord
 
           def escape_hstore(value)
             if value.nil?
-              'NULL'
+              "NULL"
             else
               if value == ""
                 '""'
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
index dcc12ae2a4..7a91272d1c 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb
@@ -25,9 +25,9 @@ module ActiveRecord
             value.sub!(/^\((.+)\)$/, '-\1') # (4)
             case value
             when /^-?\D+[\d,]+\.\d{2}$/  # (1)
-              value.gsub!(/[^-\d.]/, '')
+              value.gsub!(/[^-\d.]/, "")
             when /^-?\D+[\d.]+,\d{2}$/  # (2)
-              value.gsub!(/[^-\d,]/, '').sub!(/,/, '.')
+              value.gsub!(/[^-\d,]/, "").sub!(/,/, ".")
             end
 
             super(value)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
index bf565bcf47..3657f20433 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb
@@ -12,10 +12,10 @@ module ActiveRecord
           def cast(value)
             case value
             when ::String
-              if value[0] == '(' && value[-1] == ')'
+              if value[0] == "(" && value[-1] == ")"
                 value = value[1...-1]
               end
-              cast(value.split(','))
+              cast(value.split(","))
             when ::Array
               value.map { |v| Float(v) }
             else
@@ -34,7 +34,7 @@ module ActiveRecord
           private
 
           def number_for_point(number)
-            number.to_s.gsub(/\.0$/, '')
+            number.to_s.gsub(/\.0$/, "")
           end
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/rails_5_1_point.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/rails_5_1_point.rb
index 4da240edb2..3a52f05091 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/rails_5_1_point.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/rails_5_1_point.rb
@@ -16,7 +16,7 @@ module ActiveRecord
             when ::String
               return if value.blank?
               
-              if value[0] == '(' && value[-1] == ')'
+              if value[0] == "(" && value[-1] == ")"
                 value = value[1...-1]
               end
               x, y = value.split(",")
@@ -39,7 +39,7 @@ module ActiveRecord
           private
 
           def number_for_point(number)
-            number.to_s.gsub(/\.0$/, '')
+            number.to_s.gsub(/\.0$/, "")
           end
 
           def build_point(x, y)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
index a8d2310035..58bf5c5640 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/filters'
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   module ConnectionAdapters
@@ -14,11 +14,11 @@ module ActiveRecord
           end
 
           def type_cast_for_schema(value)
-            value.inspect.gsub('Infinity', '::Float::INFINITY')
+            value.inspect.gsub("Infinity", "::Float::INFINITY")
           end
 
           def cast_value(value)
-            return if value == 'empty'
+            return if value == "empty"
             return value unless value.is_a?(::String)
 
             extracted = extract_bounds(value)
@@ -60,16 +60,16 @@ module ActiveRecord
           end
 
           def type_cast_single_for_database(value)
-            infinity?(value) ? '' : @subtype.serialize(value)
+            infinity?(value) ? "" : @subtype.serialize(value)
           end
 
           def extract_bounds(value)
-            from, to = value[1..-2].split(',')
+            from, to = value[1..-2].split(",")
             {
-              from:          (value[1] == ',' || from == '-infinity') ? infinity(negative: true) : from,
-              to:            (value[-2] == ',' || to == 'infinity') ? infinity : to,
-              exclude_start: (value[0] == '('),
-              exclude_end:   (value[-1] == ')')
+              from:          (value[1] == "," || from == "-infinity") ? infinity(negative: true) : from,
+              to:            (value[-2] == "," || to == "infinity") ? infinity : to,
+              exclude_start: (value[0] == "("),
+              exclude_end:   (value[-1] == ")")
             }
           end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
index 6155e53632..3a75e8d69d 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb
@@ -13,13 +13,13 @@ module ActiveRecord
           end
 
           def run(records)
-            nodes = records.reject { |row| @store.key? row['oid'].to_i }
-            mapped, nodes = nodes.partition { |row| @store.key? row['typname'] }
-            ranges, nodes = nodes.partition { |row| row['typtype'] == 'r'.freeze }
-            enums, nodes = nodes.partition { |row| row['typtype'] == 'e'.freeze }
-            domains, nodes = nodes.partition { |row| row['typtype'] == 'd'.freeze }
-            arrays, nodes = nodes.partition { |row| row['typinput'] == 'array_in'.freeze }
-            composites, nodes = nodes.partition { |row| row['typelem'].to_i != 0 }
+            nodes = records.reject { |row| @store.key? row["oid"].to_i }
+            mapped, nodes = nodes.partition { |row| @store.key? row["typname"] }
+            ranges, nodes = nodes.partition { |row| row["typtype"] == "r".freeze }
+            enums, nodes = nodes.partition { |row| row["typtype"] == "e".freeze }
+            domains, nodes = nodes.partition { |row| row["typtype"] == "d".freeze }
+            arrays, nodes = nodes.partition { |row| row["typinput"] == "array_in".freeze }
+            composites, nodes = nodes.partition { |row| row["typelem"].to_i != 0 }
 
             mapped.each     { |row| register_mapped_type(row)    }
             enums.each      { |row| register_enum_type(row)      }
@@ -43,36 +43,36 @@ module ActiveRecord
 
           private
           def register_mapped_type(row)
-            alias_type row['oid'], row['typname']
+            alias_type row["oid"], row["typname"]
           end
 
           def register_enum_type(row)
-            register row['oid'], OID::Enum.new
+            register row["oid"], OID::Enum.new
           end
 
           def register_array_type(row)
-            register_with_subtype(row['oid'], row['typelem'].to_i) do |subtype|
-              OID::Array.new(subtype, row['typdelim'])
+            register_with_subtype(row["oid"], row["typelem"].to_i) do |subtype|
+              OID::Array.new(subtype, row["typdelim"])
             end
           end
 
           def register_range_type(row)
-            register_with_subtype(row['oid'], row['rngsubtype'].to_i) do |subtype|
-              OID::Range.new(subtype, row['typname'].to_sym)
+            register_with_subtype(row["oid"], row["rngsubtype"].to_i) do |subtype|
+              OID::Range.new(subtype, row["typname"].to_sym)
             end
           end
 
           def register_domain_type(row)
             if base_type = @store.lookup(row["typbasetype"].to_i)
-              register row['oid'], base_type
+              register row["oid"], base_type
             else
               warn "unknown base type (OID: #{row["typbasetype"]}) for domain #{row["typname"]}."
             end
           end
 
           def register_composite_type(row)
-            if subtype = @store.lookup(row['typelem'].to_i)
-              register row['oid'], OID::Vector.new(row['typdelim'], subtype)
+            if subtype = @store.lookup(row["typelem"].to_i)
+              register row["oid"], OID::Vector.new(row["typdelim"], subtype)
             end
           end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
index 9fcf8dbb95..90e88b1f3c 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -58,7 +58,7 @@ module ActiveRecord
         def quote_default_expression(value, column) # :nodoc:
           if value.is_a?(Proc)
             value.call
-          elsif column.type == :uuid && value.include?('()')
+          elsif column.type == :uuid && value.include?("()")
             value # Does not quote function default values for UUID columns
           elsif column.respond_to?(:array?)
             value = type_cast_from_column(column, value)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
index 6399bddbee..a11dbe7dce 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb
@@ -31,7 +31,7 @@ module ActiveRecord
         # a record (as primary keys cannot be +nil+). This might be done via the
         # +SecureRandom.uuid+ method and a +before_save+ callback, for instance.
         def primary_key(name, type = :primary_key, **options)
-          options[:default] = options.fetch(:default, 'uuid_generate_v4()') if type == :uuid
+          options[:default] = options.fetch(:default, "uuid_generate_v4()") if type == :uuid
           super
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
index a1e10fd364..2ed8f29b24 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
@@ -5,7 +5,7 @@ module ActiveRecord
         def column_spec_for_primary_key(column)
           spec = super
           if schema_type(column) == :uuid
-            spec[:default] ||= 'nil'
+            spec[:default] ||= "nil"
           end
           spec
         end
@@ -13,7 +13,7 @@ module ActiveRecord
         # Adds +:array+ option to the default set
         def prepare_column_options(column)
           spec = super
-          spec[:array] = 'true' if column.array?
+          spec[:array] = "true" if column.array?
           spec
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 4cf6d4b14a..55c5fcafa6 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/strip'
+require "active_support/core_ext/string/strip"
 
 module ActiveRecord
   module ConnectionAdapters
@@ -36,7 +36,7 @@ module ActiveRecord
         #   create_database config[:database], config
         #   create_database 'foo_development', encoding: 'unicode'
         def create_database(name, options = {})
-          options = { encoding: 'utf8' }.merge!(options.symbolize_keys)
+          options = { encoding: "utf8" }.merge!(options.symbolize_keys)
 
           option_string = options.inject("") do |memo, (key, value)|
             memo += case key
@@ -78,11 +78,11 @@ module ActiveRecord
             MSG
           end
 
-          select_values("SELECT tablename FROM pg_tables WHERE schemaname = ANY(current_schemas(false))", 'SCHEMA')
+          select_values("SELECT tablename FROM pg_tables WHERE schemaname = ANY(current_schemas(false))", "SCHEMA")
         end
 
         def data_sources # :nodoc
-          select_values(<<-SQL, 'SCHEMA')
+          select_values(<<-SQL, "SCHEMA")
             SELECT c.relname
             FROM pg_class c
             LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
@@ -108,7 +108,7 @@ module ActiveRecord
           name = Utils.extract_schema_qualified_name(name.to_s)
           return false unless name.identifier
 
-          select_value(<<-SQL, 'SCHEMA').to_i > 0
+          select_value(<<-SQL, "SCHEMA").to_i > 0
               SELECT COUNT(*)
               FROM pg_class c
               LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
@@ -119,7 +119,7 @@ module ActiveRecord
         end
 
         def views # :nodoc:
-          select_values(<<-SQL, 'SCHEMA')
+          select_values(<<-SQL, "SCHEMA")
             SELECT c.relname
             FROM pg_class c
             LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
@@ -132,7 +132,7 @@ module ActiveRecord
           name = Utils.extract_schema_qualified_name(view_name.to_s)
           return false unless name.identifier
 
-          select_values(<<-SQL, 'SCHEMA').any?
+          select_values(<<-SQL, "SCHEMA").any?
             SELECT c.relname
             FROM pg_class c
             LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
@@ -148,7 +148,7 @@ module ActiveRecord
 
         # Returns true if schema exists.
         def schema_exists?(name)
-          select_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = '#{name}'", 'SCHEMA').to_i > 0
+          select_value("SELECT COUNT(*) FROM pg_namespace WHERE nspname = '#{name}'", "SCHEMA").to_i > 0
         end
 
         # Verifies existence of an index with a given name.
@@ -156,7 +156,7 @@ module ActiveRecord
           table = Utils.extract_schema_qualified_name(table_name.to_s)
           index = Utils.extract_schema_qualified_name(index_name.to_s)
 
-          select_value(<<-SQL, 'SCHEMA').to_i > 0
+          select_value(<<-SQL, "SCHEMA").to_i > 0
             SELECT COUNT(*)
             FROM pg_class t
             INNER JOIN pg_index d ON t.oid = d.indrelid
@@ -173,7 +173,7 @@ module ActiveRecord
         def indexes(table_name, name = nil)
           table = Utils.extract_schema_qualified_name(table_name.to_s)
 
-          result = query(<<-SQL, 'SCHEMA')
+          result = query(<<-SQL, "SCHEMA")
             SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
                             pg_catalog.obj_description(i.oid, 'pg_class') AS comment,
             (SELECT COUNT(*) FROM pg_opclass o
@@ -246,7 +246,7 @@ module ActiveRecord
         def table_comment(table_name) # :nodoc:
           name = Utils.extract_schema_qualified_name(table_name.to_s)
           if name.identifier
-            select_value(<<-SQL.strip_heredoc, 'SCHEMA')
+            select_value(<<-SQL.strip_heredoc, "SCHEMA")
               SELECT pg_catalog.obj_description(c.oid, 'pg_class')
               FROM pg_catalog.pg_class c
                 LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
@@ -259,32 +259,32 @@ module ActiveRecord
 
         # Returns the current database name.
         def current_database
-          select_value('select current_database()', 'SCHEMA')
+          select_value("select current_database()", "SCHEMA")
         end
 
         # Returns the current schema name.
         def current_schema
-          select_value('SELECT current_schema', 'SCHEMA')
+          select_value("SELECT current_schema", "SCHEMA")
         end
 
         # Returns the current database encoding format.
         def encoding
-          select_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname LIKE '#{current_database}'", 'SCHEMA')
+          select_value("SELECT pg_encoding_to_char(encoding) FROM pg_database WHERE datname LIKE '#{current_database}'", "SCHEMA")
         end
 
         # Returns the current database collation.
         def collation
-          select_value("SELECT datcollate FROM pg_database WHERE datname LIKE '#{current_database}'", 'SCHEMA')
+          select_value("SELECT datcollate FROM pg_database WHERE datname LIKE '#{current_database}'", "SCHEMA")
         end
 
         # Returns the current database ctype.
         def ctype
-          select_value("SELECT datctype FROM pg_database WHERE datname LIKE '#{current_database}'", 'SCHEMA')
+          select_value("SELECT datctype FROM pg_database WHERE datname LIKE '#{current_database}'", "SCHEMA")
         end
 
         # Returns an array of schema names.
         def schema_names
-          select_values(<<-SQL, 'SCHEMA')
+          select_values(<<-SQL, "SCHEMA")
             SELECT nspname
               FROM pg_namespace
              WHERE nspname !~ '^pg_.*'
@@ -310,28 +310,28 @@ module ActiveRecord
         # This should be not be called manually but set in database.yml.
         def schema_search_path=(schema_csv)
           if schema_csv
-            execute("SET search_path TO #{schema_csv}", 'SCHEMA')
+            execute("SET search_path TO #{schema_csv}", "SCHEMA")
             @schema_search_path = schema_csv
           end
         end
 
         # Returns the active schema search path.
         def schema_search_path
-          @schema_search_path ||= select_value('SHOW search_path', 'SCHEMA')
+          @schema_search_path ||= select_value("SHOW search_path", "SCHEMA")
         end
 
         # Returns the current client message level.
         def client_min_messages
-          select_value('SHOW client_min_messages', 'SCHEMA')
+          select_value("SHOW client_min_messages", "SCHEMA")
         end
 
         # Set the client message level.
         def client_min_messages=(level)
-          execute("SET client_min_messages TO '#{level}'", 'SCHEMA')
+          execute("SET client_min_messages TO '#{level}'", "SCHEMA")
         end
 
         # Returns the sequence name for a table's primary key or some other specified key.
-        def default_sequence_name(table_name, pk = 'id') #:nodoc:
+        def default_sequence_name(table_name, pk = "id") #:nodoc:
           result = serial_sequence(table_name, pk)
           return nil unless result
           Utils.extract_schema_qualified_name(result).to_s
@@ -340,7 +340,7 @@ module ActiveRecord
         end
 
         def serial_sequence(table, column)
-          select_value("SELECT pg_get_serial_sequence('#{table}', '#{column}')", 'SCHEMA')
+          select_value("SELECT pg_get_serial_sequence('#{table}', '#{column}')", "SCHEMA")
         end
 
         # Sets the sequence of a table's primary key to the specified value.
@@ -351,7 +351,7 @@ module ActiveRecord
             if sequence
               quoted_sequence = quote_table_name(sequence)
 
-              select_value("SELECT setval('#{quoted_sequence}', #{value})", 'SCHEMA')
+              select_value("SELECT setval('#{quoted_sequence}', #{value})", "SCHEMA")
             else
               @logger.warn "#{table} has primary key #{pk} with no default sequence." if @logger
             end
@@ -374,7 +374,7 @@ module ActiveRecord
           if pk && sequence
             quoted_sequence = quote_table_name(sequence)
 
-            select_value(<<-end_sql, 'SCHEMA')
+            select_value(<<-end_sql, "SCHEMA")
               SELECT setval('#{quoted_sequence}', (SELECT COALESCE(MAX(#{quote_column_name pk})+(SELECT increment_by FROM #{quoted_sequence}), (SELECT min_value FROM #{quoted_sequence})) FROM #{quote_table_name(table)}), false)
             end_sql
           end
@@ -384,7 +384,7 @@ module ActiveRecord
         def pk_and_sequence_for(table) #:nodoc:
           # First try looking for a sequence with a dependency on the
           # given table's primary key.
-          result = query(<<-end_sql, 'SCHEMA')[0]
+          result = query(<<-end_sql, "SCHEMA")[0]
             SELECT attr.attname, nsp.nspname, seq.relname
             FROM pg_class      seq,
                  pg_attribute  attr,
@@ -404,7 +404,7 @@ module ActiveRecord
           end_sql
 
           if result.nil? or result.empty?
-            result = query(<<-end_sql, 'SCHEMA')[0]
+            result = query(<<-end_sql, "SCHEMA")[0]
               SELECT attr.attname, nsp.nspname,
                 CASE
                   WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL
@@ -435,7 +435,7 @@ module ActiveRecord
         end
 
         def primary_keys(table_name) # :nodoc:
-          select_values(<<-SQL.strip_heredoc, 'SCHEMA')
+          select_values(<<-SQL.strip_heredoc, "SCHEMA")
             WITH pk_constraint AS (
               SELECT conrelid, unnest(conkey) AS connum FROM pg_constraint
               WHERE contype = 'p'
@@ -583,7 +583,7 @@ module ActiveRecord
         end
 
         def foreign_keys(table_name)
-          fk_info = select_all(<<-SQL.strip_heredoc, 'SCHEMA')
+          fk_info = select_all(<<-SQL.strip_heredoc, "SCHEMA")
             SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
             FROM pg_constraint c
             JOIN pg_class t1 ON c.conrelid = t1.oid
@@ -599,23 +599,23 @@ module ActiveRecord
 
           fk_info.map do |row|
             options = {
-              column: row['column'],
-              name: row['name'],
-              primary_key: row['primary_key']
+              column: row["column"],
+              name: row["name"],
+              primary_key: row["primary_key"]
             }
 
-            options[:on_delete] = extract_foreign_key_action(row['on_delete'])
-            options[:on_update] = extract_foreign_key_action(row['on_update'])
+            options[:on_delete] = extract_foreign_key_action(row["on_delete"])
+            options[:on_update] = extract_foreign_key_action(row["on_update"])
 
-            ForeignKeyDefinition.new(table_name, row['to_table'], options)
+            ForeignKeyDefinition.new(table_name, row["to_table"], options)
           end
         end
 
         def extract_foreign_key_action(specifier) # :nodoc:
           case specifier
-          when 'c'; :cascade
-          when 'n'; :nullify
-          when 'r'; :restrict
+          when "c"; :cascade
+          when "n"; :nullify
+          when "r"; :restrict
           end
         end
 
@@ -626,32 +626,32 @@ module ActiveRecord
         # Maps logical Rails types to PostgreSQL-specific data types.
         def type_to_sql(type, limit = nil, precision = nil, scale = nil, array = nil)
           sql = case type.to_s
-          when 'binary'
+          when "binary"
             # PostgreSQL doesn't support limits on binary (bytea) columns.
             # The hard limit is 1GB, because of a 32-bit size field, and TOAST.
             case limit
             when nil, 0..0x3fffffff; super(type)
             else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
             end
-          when 'text'
+          when "text"
             # PostgreSQL doesn't support limits on text columns.
             # The hard limit is 1GB, according to section 8.3 in the manual.
             case limit
             when nil, 0..0x3fffffff; super(type)
             else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.")
             end
-          when 'integer'
+          when "integer"
             case limit
-            when 1, 2; 'smallint'
-            when nil, 3, 4; 'integer'
-            when 5..8; 'bigint'
+            when 1, 2; "smallint"
+            when nil, 3, 4; "integer"
+            when 5..8; "bigint"
             else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with scale 0 instead.")
             end
           else
             super(type, limit, precision, scale)
           end
 
-          sql << '[]' if array && type != :primary_key
+          sql << "[]" if array && type != :primary_key
           sql
         end
 
@@ -662,11 +662,11 @@ module ActiveRecord
               # Convert Arel node to string
               s = s.to_sql unless s.is_a?(String)
               # Remove any ASC/DESC modifiers
-              s.gsub(/\s+(?:ASC|DESC)\b/i, '')
-               .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, '')
+              s.gsub(/\s+(?:ASC|DESC)\b/i, "")
+               .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, "")
             }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }
 
-          [super, *order_columns].join(', ')
+          [super, *order_columns].join(", ")
         end
 
         def fetch_type_metadata(column_name, sql_type, oid, fmod)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 8a1fdc9f92..ced5fed2e2 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -1,6 +1,6 @@
 # Make sure we're using pg high enough for type casts and Ruby 2.2+ compatibility
-gem 'pg', '~> 0.18'
-require 'pg'
+gem "pg", "~> 0.18"
+require "pg"
 
 require "active_record/connection_adapters/abstract_adapter"
 require "active_record/connection_adapters/postgresql/column"
@@ -67,7 +67,7 @@ module ActiveRecord
     # In addition, default connection parameters of libpq can be set per environment variables.
     # See http://www.postgresql.org/docs/current/static/libpq-envars.html .
     class PostgreSQLAdapter < AbstractAdapter
-      ADAPTER_NAME = 'PostgreSQL'.freeze
+      ADAPTER_NAME = "PostgreSQL".freeze
 
       NATIVE_DATABASE_TYPES = {
         primary_key: "serial primary key",
@@ -173,7 +173,7 @@ module ActiveRecord
       end
 
       def index_algorithms
-        { concurrently: 'CONCURRENTLY' }
+        { concurrently: "CONCURRENTLY" }
       end
 
       class StatementPool < ConnectionAdapters::StatementPool
@@ -227,7 +227,7 @@ module ActiveRecord
 
         @type_map = Type::HashLookupTypeMap.new
         initialize_type_map(type_map)
-        @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"]
+        @local_tz = execute("SHOW TIME ZONE", "SCHEMA").first["TimeZone"]
         @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
       end
 
@@ -242,7 +242,7 @@ module ActiveRecord
 
       # Is this connection alive and ready for queries?
       def active?
-        @connection.query 'SELECT 1'
+        @connection.query "SELECT 1"
         true
       rescue PGError
         false
@@ -259,9 +259,9 @@ module ActiveRecord
         clear_cache!
         reset_transaction
         unless @connection.transaction_status == ::PG::PQTRANS_IDLE
-          @connection.query 'ROLLBACK'
+          @connection.query "ROLLBACK"
         end
-        @connection.query 'DISCARD ALL'
+        @connection.query "DISCARD ALL"
         configure_connection
       end
 
@@ -287,7 +287,7 @@ module ActiveRecord
       end
 
       def set_standard_conforming_strings
-        execute('SET standard_conforming_strings = on', 'SCHEMA')
+        execute("SET standard_conforming_strings = on", "SCHEMA")
       end
 
       def supports_ddl_transactions?
@@ -344,7 +344,7 @@ module ActiveRecord
       def extension_enabled?(name)
         if supports_extensions?
           res = exec_query "SELECT EXISTS(SELECT * FROM pg_available_extensions WHERE name = '#{name}' AND installed_version IS NOT NULL) as enabled",
-            'SCHEMA'
+            "SCHEMA"
           res.cast_values.first
         end
       end
@@ -359,7 +359,7 @@ module ActiveRecord
 
       # Returns the configured supported identifier length supported by PostgreSQL
       def table_alias_length
-        @table_alias_length ||= query('SHOW max_identifier_length', 'SCHEMA')[0][0].to_i
+        @table_alias_length ||= query("SHOW max_identifier_length", "SCHEMA")[0][0].to_i
       end
 
       # Set the authorized user for this session
@@ -381,7 +381,7 @@ module ActiveRecord
       end
 
       def lookup_cast_type(sql_type) # :nodoc:
-        oid = execute("SELECT #{quote(sql_type)}::regtype::oid", "SCHEMA").first['oid'].to_i
+        oid = execute("SELECT #{quote(sql_type)}::regtype::oid", "SCHEMA").first["oid"].to_i
         super(oid)
       end
 
@@ -430,7 +430,7 @@ module ActiveRecord
 
       private
 
-        def get_oid_type(oid, fmod, column_name, sql_type = '') # :nodoc:
+        def get_oid_type(oid, fmod, column_name, sql_type = "") # :nodoc:
           if !type_map.key?(oid)
             load_additional_types(type_map, [oid])
           end
@@ -444,51 +444,51 @@ module ActiveRecord
         end
 
         def initialize_type_map(m) # :nodoc:
-          register_class_with_limit m, 'int2', Type::Integer
-          register_class_with_limit m, 'int4', Type::Integer
-          register_class_with_limit m, 'int8', Type::Integer
-          m.alias_type 'oid', 'int2'
-          m.register_type 'float4', Type::Float.new
-          m.alias_type 'float8', 'float4'
-          m.register_type 'text', Type::Text.new
-          register_class_with_limit m, 'varchar', Type::String
-          m.alias_type 'char', 'varchar'
-          m.alias_type 'name', 'varchar'
-          m.alias_type 'bpchar', 'varchar'
-          m.register_type 'bool', Type::Boolean.new
-          register_class_with_limit m, 'bit', OID::Bit
-          register_class_with_limit m, 'varbit', OID::BitVarying
-          m.alias_type 'timestamptz', 'timestamp'
-          m.register_type 'date', Type::Date.new
-
-          m.register_type 'money', OID::Money.new
-          m.register_type 'bytea', OID::Bytea.new
-          m.register_type 'point', OID::Point.new
-          m.register_type 'hstore', OID::Hstore.new
-          m.register_type 'json', OID::Json.new
-          m.register_type 'jsonb', OID::Jsonb.new
-          m.register_type 'cidr', OID::Cidr.new
-          m.register_type 'inet', OID::Inet.new
-          m.register_type 'uuid', OID::Uuid.new
-          m.register_type 'xml', OID::Xml.new
-          m.register_type 'tsvector', OID::SpecializedString.new(:tsvector)
-          m.register_type 'macaddr', OID::SpecializedString.new(:macaddr)
-          m.register_type 'citext', OID::SpecializedString.new(:citext)
-          m.register_type 'ltree', OID::SpecializedString.new(:ltree)
-          m.register_type 'line', OID::SpecializedString.new(:line)
-          m.register_type 'lseg', OID::SpecializedString.new(:lseg)
-          m.register_type 'box', OID::SpecializedString.new(:box)
-          m.register_type 'path', OID::SpecializedString.new(:path)
-          m.register_type 'polygon', OID::SpecializedString.new(:polygon)
-          m.register_type 'circle', OID::SpecializedString.new(:circle)
+          register_class_with_limit m, "int2", Type::Integer
+          register_class_with_limit m, "int4", Type::Integer
+          register_class_with_limit m, "int8", Type::Integer
+          m.alias_type "oid", "int2"
+          m.register_type "float4", Type::Float.new
+          m.alias_type "float8", "float4"
+          m.register_type "text", Type::Text.new
+          register_class_with_limit m, "varchar", Type::String
+          m.alias_type "char", "varchar"
+          m.alias_type "name", "varchar"
+          m.alias_type "bpchar", "varchar"
+          m.register_type "bool", Type::Boolean.new
+          register_class_with_limit m, "bit", OID::Bit
+          register_class_with_limit m, "varbit", OID::BitVarying
+          m.alias_type "timestamptz", "timestamp"
+          m.register_type "date", Type::Date.new
+
+          m.register_type "money", OID::Money.new
+          m.register_type "bytea", OID::Bytea.new
+          m.register_type "point", OID::Point.new
+          m.register_type "hstore", OID::Hstore.new
+          m.register_type "json", OID::Json.new
+          m.register_type "jsonb", OID::Jsonb.new
+          m.register_type "cidr", OID::Cidr.new
+          m.register_type "inet", OID::Inet.new
+          m.register_type "uuid", OID::Uuid.new
+          m.register_type "xml", OID::Xml.new
+          m.register_type "tsvector", OID::SpecializedString.new(:tsvector)
+          m.register_type "macaddr", OID::SpecializedString.new(:macaddr)
+          m.register_type "citext", OID::SpecializedString.new(:citext)
+          m.register_type "ltree", OID::SpecializedString.new(:ltree)
+          m.register_type "line", OID::SpecializedString.new(:line)
+          m.register_type "lseg", OID::SpecializedString.new(:lseg)
+          m.register_type "box", OID::SpecializedString.new(:box)
+          m.register_type "path", OID::SpecializedString.new(:path)
+          m.register_type "polygon", OID::SpecializedString.new(:polygon)
+          m.register_type "circle", OID::SpecializedString.new(:circle)
 
           # FIXME: why are we keeping these types as strings?
-          m.alias_type 'interval', 'varchar'
+          m.alias_type "interval", "varchar"
 
-          register_class_with_precision m, 'time', Type::Time
-          register_class_with_precision m, 'timestamp', OID::DateTime
+          register_class_with_precision m, "time", Type::Time
+          register_class_with_precision m, "timestamp", OID::DateTime
 
-          m.register_type 'numeric' do |_, fmod, sql_type|
+          m.register_type "numeric" do |_, fmod, sql_type|
             precision = extract_precision(sql_type)
             scale = extract_scale(sql_type)
 
@@ -534,7 +534,7 @@ module ActiveRecord
                 $1.gsub("''".freeze, "'".freeze)
               end
             # Boolean types
-            when 'true'.freeze, 'false'.freeze
+            when "true".freeze, "false".freeze
               default
             # Numeric types
             when /\A\(?(-?\d+(\.\d*)?)\)?(::bigint)?\z/
@@ -579,7 +579,7 @@ module ActiveRecord
             query += initializer.query_conditions_for_initial_load(type_map)
           end
 
-          execute_and_clear(query, 'SCHEMA', []) do |records|
+          execute_and_clear(query, "SCHEMA", []) do |records|
             initializer.run(records)
           end
         end
@@ -634,7 +634,7 @@ module ActiveRecord
         #
         # Check here for more details:
         # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573
-        CACHED_PLAN_HEURISTIC = 'cached plan must not change result type'.freeze
+        CACHED_PLAN_HEURISTIC = "cached plan must not change result type".freeze
         def is_cached_plan_failure?(e)
           pgerror = e.cause
           code = pgerror.result.result_error_field(PGresult::PG_DIAG_SQLSTATE)
@@ -690,7 +690,7 @@ module ActiveRecord
           if @config[:encoding]
             @connection.set_client_encoding(@config[:encoding])
           end
-          self.client_min_messages = @config[:min_messages] || 'warning'
+          self.client_min_messages = @config[:min_messages] || "warning"
           self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]
 
           # Use standard-conforming strings so we don't have to do the E'...' dance.
@@ -700,27 +700,27 @@ module ActiveRecord
           # TIMESTAMP WITH ZONE types in UTC.
           # (SET TIME ZONE does not use an equals sign like other SET variables)
           if ActiveRecord::Base.default_timezone == :utc
-            execute("SET time zone 'UTC'", 'SCHEMA')
+            execute("SET time zone 'UTC'", "SCHEMA")
           elsif @local_tz
-            execute("SET time zone '#{@local_tz}'", 'SCHEMA')
+            execute("SET time zone '#{@local_tz}'", "SCHEMA")
           end
 
           # SET statements from :variables config hash
           # http://www.postgresql.org/docs/current/static/sql-set.html
           variables = @config[:variables] || {}
           variables.map do |k, v|
-            if v == ':default' || v == :default
+            if v == ":default" || v == :default
               # Sets the value to the global or compile default
-              execute("SET SESSION #{k} TO DEFAULT", 'SCHEMA')
+              execute("SET SESSION #{k} TO DEFAULT", "SCHEMA")
             elsif !v.nil?
-              execute("SET SESSION #{k} TO #{quote(v)}", 'SCHEMA')
+              execute("SET SESSION #{k} TO #{quote(v)}", "SCHEMA")
             end
           end
         end
 
         # Returns the current ID of a table's sequence.
         def last_insert_id_result(sequence_name) # :nodoc:
-          exec_query("SELECT currval('#{sequence_name}')", 'SQL')
+          exec_query("SELECT currval('#{sequence_name}')", "SQL")
         end
 
         # Returns the list of a table's column names, data types, and default values.
@@ -742,7 +742,7 @@ module ActiveRecord
         #  - format_type includes the column size constraint, e.g. varchar(50)
         #  - ::regclass is a function that gives the id for a table name
         def column_definitions(table_name) # :nodoc:
-          query(<<-end_sql, 'SCHEMA')
+          query(<<-end_sql, "SCHEMA")
               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
                      pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod,
              (SELECT c.collname FROM pg_collation c, pg_type t
@@ -794,13 +794,13 @@ module ActiveRecord
 
         def add_pg_decoders
           coders_by_name = {
-            'int2' => PG::TextDecoder::Integer,
-            'int4' => PG::TextDecoder::Integer,
-            'int8' => PG::TextDecoder::Integer,
-            'oid' => PG::TextDecoder::Integer,
-            'float4' => PG::TextDecoder::Float,
-            'float8' => PG::TextDecoder::Float,
-            'bool' => PG::TextDecoder::Boolean,
+            "int2" => PG::TextDecoder::Integer,
+            "int4" => PG::TextDecoder::Integer,
+            "int8" => PG::TextDecoder::Integer,
+            "oid" => PG::TextDecoder::Integer,
+            "float4" => PG::TextDecoder::Float,
+            "float8" => PG::TextDecoder::Float,
+            "bool" => PG::TextDecoder::Boolean,
           }
           known_coder_types = coders_by_name.keys.map { |n| quote(n) }
           query = <<-SQL % known_coder_types.join(", ")
@@ -810,7 +810,7 @@ module ActiveRecord
           SQL
           coders = execute_and_clear(query, "SCHEMA", []) do |result|
             result
-              .map { |row| construct_coder(row, coders_by_name[row['typname']]) }
+              .map { |row| construct_coder(row, coders_by_name[row["typname"]]) }
               .compact
           end
 
@@ -821,7 +821,7 @@ module ActiveRecord
 
         def construct_coder(row, coder_class)
           return unless coder_class
-          coder_class.new(oid: row['oid'].to_i, name: row['typname'])
+          coder_class.new(oid: row["oid"].to_i, name: row["typname"])
         end
 
         ActiveRecord::Type.add_modifier({ array: true }, OID::Array, adapter: :postgresql)
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb
index a946f5ebd0..6fe3e1211e 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/explain_pretty_printer.rb
@@ -10,7 +10,7 @@ module ActiveRecord
         #
         def pp(result)
           result.rows.map do |row|
-            row.join('|')
+            row.join("|")
           end.join("\n") + "\n"
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
index 41ed784d2e..47de43dfc3 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb
@@ -1,11 +1,11 @@
-require 'active_record/connection_adapters/abstract_adapter'
-require 'active_record/connection_adapters/statement_pool'
-require 'active_record/connection_adapters/sqlite3/explain_pretty_printer'
-require 'active_record/connection_adapters/sqlite3/quoting'
-require 'active_record/connection_adapters/sqlite3/schema_creation'
+require "active_record/connection_adapters/abstract_adapter"
+require "active_record/connection_adapters/statement_pool"
+require "active_record/connection_adapters/sqlite3/explain_pretty_printer"
+require "active_record/connection_adapters/sqlite3/quoting"
+require "active_record/connection_adapters/sqlite3/schema_creation"
 
-gem 'sqlite3', '~> 1.3.6'
-require 'sqlite3'
+gem "sqlite3", "~> 1.3.6"
+require "sqlite3"
 
 module ActiveRecord
   module ConnectionHandling # :nodoc:
@@ -18,7 +18,7 @@ module ActiveRecord
       # Allow database path relative to Rails.root, but only if the database
       # path is not the special path that tells sqlite to build a database only
       # in memory.
-      if ':memory:' != config[:database]
+      if ":memory:" != config[:database]
         config[:database] = File.expand_path(config[:database], Rails.root) if defined?(Rails.root)
         dirname = File.dirname(config[:database])
         Dir.mkdir(dirname) unless File.directory?(dirname)
@@ -49,12 +49,12 @@ module ActiveRecord
     #
     # * <tt>:database</tt> - Path to the database file.
     class SQLite3Adapter < AbstractAdapter
-      ADAPTER_NAME = 'SQLite'.freeze
+      ADAPTER_NAME = "SQLite".freeze
 
       include SQLite3::Quoting
 
       NATIVE_DATABASE_TYPES = {
-        primary_key:  'INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL',
+        primary_key:  "INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL",
         string:       { name: "varchar" },
         text:         { name: "text" },
         integer:      { name: "integer" },
@@ -99,7 +99,7 @@ module ActiveRecord
       end
 
       def supports_partial_index?
-        sqlite_version >= '3.8.0'
+        sqlite_version >= "3.8.0"
       end
 
       # Returns true, since this connection adapter supports prepared statement
@@ -130,7 +130,7 @@ module ActiveRecord
       end
 
       def supports_multi_insert?
-        sqlite_version >= '3.7.11'
+        sqlite_version >= "3.7.11"
       end
 
       def active?
@@ -184,7 +184,7 @@ module ActiveRecord
 
       def explain(arel, binds = [])
         sql = "EXPLAIN QUERY PLAN #{to_sql(arel, binds)}"
-        SQLite3::ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', []))
+        SQLite3::ExplainPrettyPrinter.new.pp(exec_query(sql, "EXPLAIN", []))
       end
 
       def exec_query(sql, name = nil, binds = [], prepare: false)
@@ -218,7 +218,7 @@ module ActiveRecord
         end
       end
 
-      def exec_delete(sql, name = 'SQL', binds = [])
+      def exec_delete(sql, name = "SQL", binds = [])
         exec_query(sql, name, binds)
         @connection.changes
       end
@@ -233,15 +233,15 @@ module ActiveRecord
       end
 
       def begin_db_transaction #:nodoc:
-        log('begin transaction',nil) { @connection.transaction }
+        log("begin transaction",nil) { @connection.transaction }
       end
 
       def commit_db_transaction #:nodoc:
-        log('commit transaction',nil) { @connection.commit }
+        log("commit transaction",nil) { @connection.commit }
       end
 
       def exec_rollback_db_transaction #:nodoc:
-        log('rollback transaction',nil) { @connection.rollback }
+        log("rollback transaction",nil) { @connection.rollback }
       end
 
       # SCHEMA STATEMENTS ========================================
@@ -263,7 +263,7 @@ module ActiveRecord
       end
 
       def data_sources
-        select_values("SELECT name FROM sqlite_master WHERE type IN ('table','view') AND name <> 'sqlite_sequence'", 'SCHEMA')
+        select_values("SELECT name FROM sqlite_master WHERE type IN ('table','view') AND name <> 'sqlite_sequence'", "SCHEMA")
       end
 
       def table_exists?(table_name)
@@ -282,11 +282,11 @@ module ActiveRecord
         sql = "SELECT name FROM sqlite_master WHERE type IN ('table','view') AND name <> 'sqlite_sequence'"
         sql << " AND name = #{quote(table_name)}"
 
-        select_values(sql, 'SCHEMA').any?
+        select_values(sql, "SCHEMA").any?
       end
 
       def views # :nodoc:
-        select_values("SELECT name FROM sqlite_master WHERE type = 'view' AND name <> 'sqlite_sequence'", 'SCHEMA')
+        select_values("SELECT name FROM sqlite_master WHERE type = 'view' AND name <> 'sqlite_sequence'", "SCHEMA")
       end
 
       def view_exists?(view_name) # :nodoc:
@@ -295,7 +295,7 @@ module ActiveRecord
         sql = "SELECT name FROM sqlite_master WHERE type = 'view' AND name <> 'sqlite_sequence'"
         sql << " AND name = #{quote(view_name)}"
 
-        select_values(sql, 'SCHEMA').any?
+        select_values(sql, "SCHEMA").any?
       end
 
       # Returns an array of +Column+ objects for the table specified by +table_name+.
@@ -311,16 +311,16 @@ module ActiveRecord
             field["dflt_value"] = $1.gsub('""', '"')
           end
 
-          collation = field['collation']
-          sql_type = field['type']
+          collation = field["collation"]
+          sql_type = field["type"]
           type_metadata = fetch_type_metadata(sql_type)
-          new_column(field['name'], field['dflt_value'], type_metadata, field['notnull'].to_i == 0, table_name, nil, collation)
+          new_column(field["name"], field["dflt_value"], type_metadata, field["notnull"].to_i == 0, table_name, nil, collation)
         end
       end
 
       # Returns an array of indexes for the given table.
       def indexes(table_name, name = nil) #:nodoc:
-        exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", 'SCHEMA').map do |row|
+        exec_query("PRAGMA index_list(#{quote_table_name(table_name)})", "SCHEMA").map do |row|
           sql = <<-SQL
             SELECT sql
             FROM sqlite_master
@@ -330,22 +330,22 @@ module ActiveRecord
             FROM sqlite_temp_master
             WHERE name=#{quote(row['name'])} AND type='index'
           SQL
-          index_sql = exec_query(sql).first['sql']
+          index_sql = exec_query(sql).first["sql"]
           match = /\sWHERE\s+(.+)$/i.match(index_sql)
           where = match[1] if match
           IndexDefinition.new(
             table_name,
-            row['name'],
-            row['unique'] != 0,
+            row["name"],
+            row["unique"] != 0,
             exec_query("PRAGMA index_info('#{row['name']}')", "SCHEMA").map { |col|
-              col['name']
+              col["name"]
             }, nil, nil, where)
         end
       end
 
       def primary_keys(table_name) # :nodoc:
-        pks = table_structure(table_name).select { |f| f['pk'] > 0 }
-        pks.sort_by { |f| f['pk'] }.map { |f| f['name'] }
+        pks = table_structure(table_name).select { |f| f["pk"] > 0 }
+        pks.sort_by { |f| f["pk"] }.map { |f| f["name"] }
       end
 
       def remove_index(table_name, options = {}) #:nodoc:
@@ -425,7 +425,7 @@ module ActiveRecord
       protected
 
         def table_structure(table_name)
-          structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})", 'SCHEMA')
+          structure = exec_query("PRAGMA table_info(#{quote_table_name(table_name)})", "SCHEMA")
           raise(ActiveRecord::StatementInvalid, "Could not find table '#{table_name}'") if structure.empty?
           table_structure_with_collation(table_name, structure)
         end
@@ -501,15 +501,15 @@ module ActiveRecord
           from_columns = columns(from).collect(&:name)
           columns = columns.find_all{|col| from_columns.include?(column_mappings[col])}
           from_columns_to_copy = columns.map { |col| column_mappings[col] }
-          quoted_columns = columns.map { |col| quote_column_name(col) } * ','
-          quoted_from_columns = from_columns_to_copy.map { |col| quote_column_name(col) } * ','
+          quoted_columns = columns.map { |col| quote_column_name(col) } * ","
+          quoted_from_columns = from_columns_to_copy.map { |col| quote_column_name(col) } * ","
 
           exec_query("INSERT INTO #{quote_table_name(to)} (#{quoted_columns})
                      SELECT #{quoted_from_columns} FROM #{quote_table_name(from)}")
         end
 
         def sqlite_version
-          @sqlite_version ||= SQLite3Adapter::Version.new(select_value('select sqlite_version(*)'))
+          @sqlite_version ||= SQLite3Adapter::Version.new(select_value("select sqlite_version(*)"))
         end
 
         def translate_exception(exception, message)
@@ -538,24 +538,24 @@ module ActiveRecord
           # Result will have following sample string
           # CREATE TABLE "users" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
           #                       "password_digest" varchar COLLATE "NOCASE");
-          result = exec_query(sql, 'SCHEMA').first
+          result = exec_query(sql, "SCHEMA").first
 
           if result
             # Splitting with left parentheses and picking up last will return all
             # columns separated with comma(,).
-            columns_string = result["sql"].split('(').last
+            columns_string = result["sql"].split("(").last
 
-            columns_string.split(',').each do |column_string|
+            columns_string.split(",").each do |column_string|
               # This regex will match the column name and collation type and will save
               # the value in $1 and $2 respectively.
               collation_hash[$1] = $2 if COLLATE_REGEX =~ column_string
             end
 
             basic_structure.map! do |column|
-              column_name = column['name']
+              column_name = column["name"]
 
               if collation_hash.has_key? column_name
-                column['collation'] = collation_hash[column_name]
+                column["collation"] = collation_hash[column_name]
               end
 
               column
diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
index f735bc697b..48e1dc1b0c 100644
--- a/activerecord/lib/active_record/connection_handling.rb
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -73,7 +73,7 @@ module ActiveRecord
       private
         def config
           @raw_config.dup.tap do |cfg|
-            if url = ENV['DATABASE_URL']
+            if url = ENV["DATABASE_URL"]
               cfg[@env] ||= {}
               cfg[@env]["url"] ||= url
             end
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 3e3a7679ac..26a00e62d1 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -1,7 +1,7 @@
-require 'thread'
-require 'active_support/core_ext/hash/indifferent_access'
-require 'active_support/core_ext/object/duplicable'
-require 'active_support/core_ext/string/filters'
+require "thread"
+require "active_support/core_ext/hash/indifferent_access"
+require "active_support/core_ext/object/duplicable"
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   module Core
@@ -253,7 +253,7 @@ module ActiveRecord
         elsif !connected?
           "#{super} (call '#{super}.connection' to establish a connection)"
         elsif table_exists?
-          attr_list = attribute_types.map { |name, type| "#{name}: #{type.type}" } * ', '
+          attr_list = attribute_types.map { |name, type| "#{name}: #{type.type}" } * ", "
           "#{super}(#{attr_list})"
         else
           "#{super}(Table doesn't exist)"
@@ -362,7 +362,7 @@ module ActiveRecord
 
       init_internals
 
-      @new_record = coder['new_record']
+      @new_record = coder["new_record"]
 
       self.class.define_attribute_methods
 
@@ -425,8 +425,8 @@ module ActiveRecord
     #   coder # => {"attributes" => {"id" => nil, ... }}
     def encode_with(coder)
       self.class.yaml_encoder.encode(@attributes, coder)
-      coder['new_record'] = new_record?
-      coder['active_record_yaml_version'] = 2
+      coder["new_record"] = new_record?
+      coder["active_record_yaml_version"] = 2
     end
 
     # Returns true if +comparison_object+ is the same exact object, or +comparison_object+
@@ -516,19 +516,19 @@ module ActiveRecord
       pp.object_address_group(self) do
         if defined?(@attributes) && @attributes
           column_names = self.class.column_names.select { |name| has_attribute?(name) || new_record? }
-          pp.seplist(column_names, proc { pp.text ',' }) do |column_name|
+          pp.seplist(column_names, proc { pp.text "," }) do |column_name|
             column_value = read_attribute(column_name)
-            pp.breakable ' '
+            pp.breakable " "
             pp.group(1) do
               pp.text column_name
-              pp.text ':'
+              pp.text ":"
               pp.breakable
               pp.pp column_value
             end
           end
         else
-          pp.breakable ' '
-          pp.text 'not initialized'
+          pp.breakable " "
+          pp.text "not initialized"
         end
       end
     end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 1b6817554d..d21f7a6126 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -75,12 +75,12 @@ module ActiveRecord
       #   #  WHERE id IN (10, 15)
       def update_counters(id, counters)
         updates = counters.map do |counter_name, value|
-          operator = value < 0 ? '-' : '+'
+          operator = value < 0 ? "-" : "+"
           quoted_column = connection.quote_column_name(counter_name)
           "#{quoted_column} = COALESCE(#{quoted_column}, 0) #{operator} #{value.abs}"
         end
 
-        unscoped.where(primary_key => id).update_all updates.join(', ')
+        unscoped.where(primary_key => id).update_all updates.join(", ")
       end
 
       # Increment a numeric field by one, via a direct SQL update.
diff --git a/activerecord/lib/active_record/dynamic_matchers.rb b/activerecord/lib/active_record/dynamic_matchers.rb
index 0bdebb3989..b41546064b 100644
--- a/activerecord/lib/active_record/dynamic_matchers.rb
+++ b/activerecord/lib/active_record/dynamic_matchers.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/regexp'
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module DynamicMatchers #:nodoc:
@@ -44,7 +44,7 @@ module ActiveRecord
         end
 
         def suffix
-          ''
+          ""
         end
       end
 
@@ -53,7 +53,7 @@ module ActiveRecord
       def initialize(model, name)
         @model           = model
         @name            = name.to_s
-        @attribute_names = @name.match(self.class.pattern)[1].split('_and_')
+        @attribute_names = @name.match(self.class.pattern)[1].split("_and_")
         @attribute_names.map! { |n| @model.attribute_aliases[n] || n }
       end
 
@@ -78,13 +78,13 @@ module ActiveRecord
       # The parameters in the signature may have reserved Ruby words, in order
       # to prevent errors, we start each param name with `_`.
       def signature
-        attribute_names.map { |name| "_#{name}" }.join(', ')
+        attribute_names.map { |name| "_#{name}" }.join(", ")
       end
 
       # Given that the parameters starts with `_`, the finder needs to use the
       # same parameter name.
       def attributes_hash
-        "{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(',') + "}"
+        "{" + attribute_names.map { |name| ":#{name} => _#{name}" }.join(",") + "}"
       end
 
       def finder
diff --git a/activerecord/lib/active_record/enum.rb b/activerecord/lib/active_record/enum.rb
index 5d401beb53..dcf1004879 100644
--- a/activerecord/lib/active_record/enum.rb
+++ b/activerecord/lib/active_record/enum.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/object/deep_dup'
+require "active_support/core_ext/object/deep_dup"
 
 module ActiveRecord
   # Declare an enum attribute where the values map to integers in the database,
@@ -216,15 +216,15 @@ module ActiveRecord
 
       def detect_enum_conflict!(enum_name, method_name, klass_method = false)
         if klass_method && dangerous_class_method?(method_name)
-          raise_conflict_error(enum_name, method_name, type: 'class')
+          raise_conflict_error(enum_name, method_name, type: "class")
         elsif !klass_method && dangerous_attribute_method?(method_name)
           raise_conflict_error(enum_name, method_name)
         elsif !klass_method && method_defined_within?(method_name, _enum_methods_module, Module)
-          raise_conflict_error(enum_name, method_name, source: 'another enum')
+          raise_conflict_error(enum_name, method_name, source: "another enum")
         end
       end
 
-      def raise_conflict_error(enum_name, method_name, type: 'instance', source: 'Active Record')
+      def raise_conflict_error(enum_name, method_name, type: "instance", source: "Active Record")
         raise ArgumentError, ENUM_CONFLICT_MESSAGE % {
           enum: enum_name,
           klass: self.name,
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
index ac27e72f2b..980b8e1baa 100644
--- a/activerecord/lib/active_record/explain.rb
+++ b/activerecord/lib/active_record/explain.rb
@@ -1,5 +1,5 @@
-require 'active_support/lazy_load_hooks'
-require 'active_record/explain_registry'
+require "active_support/lazy_load_hooks"
+require "active_record/explain_registry"
 
 module ActiveRecord
   module Explain
diff --git a/activerecord/lib/active_record/explain_registry.rb b/activerecord/lib/active_record/explain_registry.rb
index b652932f9c..ef1ce3dc85 100644
--- a/activerecord/lib/active_record/explain_registry.rb
+++ b/activerecord/lib/active_record/explain_registry.rb
@@ -1,4 +1,4 @@
-require 'active_support/per_thread_registry'
+require "active_support/per_thread_registry"
 
 module ActiveRecord
   # This is a thread locals registry for EXPLAIN. For example
diff --git a/activerecord/lib/active_record/explain_subscriber.rb b/activerecord/lib/active_record/explain_subscriber.rb
index 90bcf5a205..706b57842f 100644
--- a/activerecord/lib/active_record/explain_subscriber.rb
+++ b/activerecord/lib/active_record/explain_subscriber.rb
@@ -1,5 +1,5 @@
-require 'active_support/notifications'
-require 'active_record/explain_registry'
+require "active_support/notifications"
+require "active_record/explain_registry"
 
 module ActiveRecord
   class ExplainSubscriber # :nodoc:
diff --git a/activerecord/lib/active_record/fixture_set/file.rb b/activerecord/lib/active_record/fixture_set/file.rb
index e4a44244e2..0888208709 100644
--- a/activerecord/lib/active_record/fixture_set/file.rb
+++ b/activerecord/lib/active_record/fixture_set/file.rb
@@ -1,5 +1,5 @@
-require 'erb'
-require 'yaml'
+require "erb"
+require "yaml"
 
 module ActiveRecord
   class FixtureSet
@@ -24,17 +24,17 @@ module ActiveRecord
       end
 
       def model_class
-        config_row['model_class']
+        config_row["model_class"]
       end
 
       private
         def rows
-          @rows ||= raw_rows.reject { |fixture_name, _| fixture_name == '_fixture' }
+          @rows ||= raw_rows.reject { |fixture_name, _| fixture_name == "_fixture" }
         end
 
         def config_row
           @config_row ||= begin
-            row = raw_rows.find { |fixture_name, _| fixture_name == '_fixture' }
+            row = raw_rows.find { |fixture_name, _| fixture_name == "_fixture" }
             if row
               row.last
             else
@@ -66,7 +66,7 @@ module ActiveRecord
         # Validate our unmarshalled data.
         def validate(data)
           unless Hash === data || YAML::Omap === data
-            raise Fixture::FormatError, 'fixture is not a hash'
+            raise Fixture::FormatError, "fixture is not a hash"
           end
 
           raise Fixture::FormatError unless data.all? { |name, row| Hash === row }
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 0ec33f7d87..601366bc38 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -1,11 +1,11 @@
-require 'erb'
-require 'yaml'
-require 'zlib'
-require 'set'
-require 'active_support/dependencies'
-require 'active_support/core_ext/digest/uuid'
-require 'active_record/fixture_set/file'
-require 'active_record/errors'
+require "erb"
+require "yaml"
+require "zlib"
+require "set"
+require "active_support/dependencies"
+require "active_support/core_ext/digest/uuid"
+require "active_record/fixture_set/file"
+require "active_record/errors"
 
 module ActiveRecord
   class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
@@ -543,7 +543,7 @@ module ActiveRecord
 
               table_rows.each_key do |table|
                 unless deleted_tables.include? table
-                  conn.delete "DELETE FROM #{conn.quote_table_name(table)}", 'Fixture Delete'
+                  conn.delete "DELETE FROM #{conn.quote_table_name(table)}", "Fixture Delete"
                 end
                 deleted_tables << table
               end
@@ -626,7 +626,7 @@ module ActiveRecord
       now = config.default_timezone == :utc ? Time.now.utc : Time.now
 
       # allow a standard key to be used for doing defaults in YAML
-      fixtures.delete('DEFAULTS')
+      fixtures.delete("DEFAULTS")
 
       # track any join tables we need to insert later
       rows = Hash.new { |h,table| h[table] = [] }
@@ -868,7 +868,7 @@ module ActiveRecord
       class_attribute :pre_loaded_fixtures
       class_attribute :config
 
-      singleton_class.deprecate 'use_transactional_fixtures=' => 'use use_transactional_tests= instead'
+      singleton_class.deprecate "use_transactional_fixtures=" => "use use_transactional_tests= instead"
 
       self.fixture_table_names = []
       self.use_instantiated_fixtures = false
@@ -918,7 +918,7 @@ module ActiveRecord
         methods = Module.new do
           fixture_set_names.each do |fs_name|
             fs_name = fs_name.to_s
-            accessor_name = fs_name.tr('/', '_').to_sym
+            accessor_name = fs_name.tr("/", "_").to_sym
 
             define_method(accessor_name) do |*fixture_names|
               force_reload = fixture_names.pop if fixture_names.last == true || fixture_names.last == :reload
@@ -962,7 +962,7 @@ module ActiveRecord
 
     def setup_fixtures(config = ActiveRecord::Base)
       if pre_loaded_fixtures && !use_transactional_tests
-        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_tests'
+        raise RuntimeError, "pre_loaded_fixtures requires use_transactional_tests"
       end
 
       @fixture_cache = {}
@@ -986,7 +986,7 @@ module ActiveRecord
         end
 
         # When connections are established in the future, begin a transaction too
-        @connection_subscriber = ActiveSupport::Notifications.subscribe('!connection.active_record') do |_, _, _, _, payload|
+        @connection_subscriber = ActiveSupport::Notifications.subscribe("!connection.active_record") do |_, _, _, _, payload|
           spec_name = payload[:spec_name] if payload.key?(:spec_name)
 
           if spec_name
@@ -1041,10 +1041,10 @@ module ActiveRecord
 
       def instantiate_fixtures
         if pre_loaded_fixtures
-          raise RuntimeError, 'Load fixtures before instantiating them.' if ActiveRecord::FixtureSet.all_loaded_fixtures.empty?
+          raise RuntimeError, "Load fixtures before instantiating them." if ActiveRecord::FixtureSet.all_loaded_fixtures.empty?
           ActiveRecord::FixtureSet.instantiate_all_loaded_fixtures(self, load_instances?)
         else
-          raise RuntimeError, 'Load fixtures before instantiating them.' if @loaded_fixtures.nil?
+          raise RuntimeError, "Load fixtures before instantiating them." if @loaded_fixtures.nil?
           @loaded_fixtures.each_value do |fixture_set|
             ActiveRecord::FixtureSet.instantiate_fixtures(self, fixture_set, load_instances?)
           end
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index b5fec57c8c..5863f622b5 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/hash/indifferent_access'
+require "active_support/core_ext/hash/indifferent_access"
 
 module ActiveRecord
   # == Single table inheritance
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index d729deb07b..c16909bbb5 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/filters'
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   module Integration
@@ -100,7 +100,7 @@ module ActiveRecord
           define_method :to_param do
             if (default = super()) &&
                  (result = send(method_name).to_s).present? &&
-                   (param = result.squish.parameterize.truncate(20, separator: /-/, omission: '')).present?
+                   (param = result.squish.parameterize.truncate(20, separator: /-/, omission: "")).present?
               "#{default}-#{param}"
             else
               default
diff --git a/activerecord/lib/active_record/internal_metadata.rb b/activerecord/lib/active_record/internal_metadata.rb
index 8b649eab0f..20d61dba67 100644
--- a/activerecord/lib/active_record/internal_metadata.rb
+++ b/activerecord/lib/active_record/internal_metadata.rb
@@ -1,5 +1,5 @@
-require 'active_record/scoping/default'
-require 'active_record/scoping/named'
+require "active_record/scoping/default"
+require "active_record/scoping/named"
 
 module ActiveRecord
   # This class is used to create a table that keeps track of values and keys such
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index 67b8efac66..5e519056a3 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -63,7 +63,7 @@ module ActiveRecord
         def increment_lock
           lock_col = self.class.locking_column
           previous_lock_value = send(lock_col).to_i
-          send(lock_col + '=', previous_lock_value + 1)
+          send(lock_col + "=", previous_lock_value + 1)
         end
 
         def _create_record(attribute_names = self.attribute_names, *) # :nodoc:
@@ -106,7 +106,7 @@ module ActiveRecord
 
           # If something went wrong, revert the version.
           rescue Exception
-            send(lock_col + '=', previous_lock_value)
+            send(lock_col + "=", previous_lock_value)
             raise
           end
         end
@@ -133,7 +133,7 @@ module ActiveRecord
         end
 
       module ClassMethods
-        DEFAULT_LOCKING_COLUMN = 'lock_version'
+        DEFAULT_LOCKING_COLUMN = "lock_version"
 
         # Returns true if the +lock_optimistically+ flag is set to true
         # (which it is, by default) and the table includes the
@@ -198,11 +198,11 @@ module ActiveRecord
       end
 
       def init_with(coder)
-        __setobj__(coder['subtype'])
+        __setobj__(coder["subtype"])
       end
 
       def encode_with(coder)
-        coder['subtype'] = __getobj__
+        coder["subtype"] = __getobj__
       end
     end
   end
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 1bb4688717..400501fb3d 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -1,6 +1,6 @@
-require 'set'
+require "set"
 require "active_support/core_ext/module/attribute_accessors"
-require 'active_support/core_ext/regexp'
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   class MigrationError < ActiveRecordError#:nodoc:
@@ -510,8 +510,8 @@ module ActiveRecord
   # Remember that you can still open your own transactions, even if you
   # are in a Migration with <tt>self.disable_ddl_transaction!</tt>.
   class Migration
-    autoload :CommandRecorder, 'active_record/migration/command_recorder'
-    autoload :Compatibility, 'active_record/migration/compatibility'
+    autoload :CommandRecorder, "active_record/migration/command_recorder"
+    autoload :Compatibility, "active_record/migration/compatibility"
 
     # This must be defined before the inherited hook, below
     class Current < Migration # :nodoc:
@@ -830,7 +830,7 @@ module ActiveRecord
     end
 
     def method_missing(method, *arguments, &block)
-      arg_list = arguments.map(&:inspect) * ', '
+      arg_list = arguments.map(&:inspect) * ", "
 
       say_with_time "#{method}(#{arg_list})" do
         unless connection.respond_to? :revert
@@ -1052,7 +1052,7 @@ module ActiveRecord
       end
 
       def migrations_paths
-        @migrations_paths ||= ['db/migrate']
+        @migrations_paths ||= ["db/migrate"]
         # just to not break things if someone uses: migrations_path = some_string
         Array(@migrations_paths)
       end
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index 74833f938f..5baca7183b 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -5,7 +5,7 @@ module ActiveRecord
         version = version.to_s
         name = "V#{version.tr('.', '_')}"
         unless const_defined?(name)
-          versions = constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete('V').tr('_', '.').inspect }
+          versions = constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete("V").tr("_", ".").inspect }
           raise ArgumentError, "Unknown migration version #{version.inspect}; expected one of #{versions.sort.join(', ')}"
         end
         const_get(name)
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index 41cebb0e34..63312a8d11 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -70,7 +70,7 @@ module ActiveRecord
       class_attribute :ignored_columns, instance_accessor: false
       self.ignored_columns = [].freeze
 
-      self.inheritance_column = 'type'
+      self.inheritance_column = "type"
 
       delegate :type_for_attribute, to: :class
     end
@@ -316,8 +316,8 @@ module ActiveRecord
         @content_columns ||= columns.reject do |c|
           c.name == primary_key ||
           c.name == inheritance_column ||
-          c.name.end_with?('_id') ||
-          c.name.end_with?('_count')
+          c.name.end_with?("_id") ||
+          c.name.end_with?("_count")
         end
       end
 
@@ -412,7 +412,7 @@ module ActiveRecord
           if parent < Base && !parent.abstract_class?
             contained = parent.table_name
             contained = contained.singularize if parent.pluralize_table_names
-            contained += '_'
+            contained += "_"
           end
 
           "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{full_table_name_suffix}"
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index fe68869143..819e181f61 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -1,6 +1,6 @@
-require 'active_support/core_ext/hash/except'
-require 'active_support/core_ext/object/try'
-require 'active_support/core_ext/hash/indifferent_access'
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/object/try"
+require "active_support/core_ext/hash/indifferent_access"
 
 module ActiveRecord
   module NestedAttributes #:nodoc:
@@ -267,7 +267,7 @@ module ActiveRecord
     #   member.avatar_attributes = {icon: 'sad'}
     #   member.avatar.width # => 200
     module ClassMethods
-      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |key, value| key == '_destroy' || value.blank? } }
+      REJECT_ALL_BLANK_PROC = proc { |attributes| attributes.all? { |key, value| key == "_destroy" || value.blank? } }
 
       # Defines an attributes writer for the specified association(s).
       #
@@ -400,12 +400,12 @@ module ActiveRecord
       attributes = attributes.with_indifferent_access
       existing_record = send(association_name)
 
-      if (options[:update_only] || !attributes['id'].blank?) && existing_record &&
-          (options[:update_only] || existing_record.id.to_s == attributes['id'].to_s)
+      if (options[:update_only] || !attributes["id"].blank?) && existing_record &&
+          (options[:update_only] || existing_record.id.to_s == attributes["id"].to_s)
         assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy]) unless call_reject_if(association_name, attributes)
 
-      elsif attributes['id'].present?
-        raise_nested_attributes_record_not_found!(association_name, attributes['id'])
+      elsif attributes["id"].present?
+        raise_nested_attributes_record_not_found!(association_name, attributes["id"])
 
       elsif !reject_new_record?(association_name, attributes)
         assignable_attributes = attributes.except(*UNASSIGNABLE_KEYS)
@@ -465,7 +465,7 @@ module ActiveRecord
 
       if attributes_collection.is_a? Hash
         keys = attributes_collection.keys
-        attributes_collection = if keys.include?('id') || keys.include?(:id)
+        attributes_collection = if keys.include?("id") || keys.include?(:id)
           [attributes_collection]
         else
           attributes_collection.values
@@ -477,7 +477,7 @@ module ActiveRecord
       existing_records = if association.loaded?
         association.target
       else
-        attribute_ids = attributes_collection.map {|a| a['id'] || a[:id] }.compact
+        attribute_ids = attributes_collection.map {|a| a["id"] || a[:id] }.compact
         attribute_ids.empty? ? [] : association.scope.where(association.klass.primary_key => attribute_ids)
       end
 
@@ -487,16 +487,16 @@ module ActiveRecord
         end
         attributes = attributes.with_indifferent_access
 
-        if attributes['id'].blank?
+        if attributes["id"].blank?
           unless reject_new_record?(association_name, attributes)
             association.build(attributes.except(*UNASSIGNABLE_KEYS))
           end
-        elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes['id'].to_s }
+        elsif existing_record = existing_records.detect { |record| record.id.to_s == attributes["id"].to_s }
           unless call_reject_if(association_name, attributes)
             # Make sure we are operating on the actual object which is in the association's
             # proxy_target array (either by finding it, or adding it if not found)
             # Take into account that the proxy_target may have changed due to callbacks
-            target_record = association.target.detect { |record| record.id.to_s == attributes['id'].to_s }
+            target_record = association.target.detect { |record| record.id.to_s == attributes["id"].to_s }
             if target_record
               existing_record = target_record
             else
@@ -506,7 +506,7 @@ module ActiveRecord
             assign_to_or_mark_for_destruction(existing_record, attributes, options[:allow_destroy])
           end
         else
-          raise_nested_attributes_record_not_found!(association_name, attributes['id'])
+          raise_nested_attributes_record_not_found!(association_name, attributes["id"])
         end
       end
     end
@@ -543,7 +543,7 @@ module ActiveRecord
 
     # Determines if a hash contains a truthy _destroy key.
     def has_destroy_flag?(hash)
-      Type::Boolean.new.cast(hash['_destroy'])
+      Type::Boolean.new.cast(hash["_destroy"])
     end
 
     # Determines if a new record should be rejected by checking
@@ -581,7 +581,7 @@ module ActiveRecord
     def raise_nested_attributes_record_not_found!(association_name, record_id)
       model = self.class._reflect_on_association(association_name).klass.name
       raise RecordNotFound.new("Couldn't find #{model} with ID=#{record_id} for #{self.class.name} with ID=#{id}",
-                               model, 'id', record_id)
+                               model, "id", record_id)
     end
   end
 end
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index 510e8a6e43..dc4af4f390 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -66,7 +66,7 @@ module ActiveRecord
       def instantiate(attributes, column_types = {})
         klass = discriminate_class_for_record(attributes)
         attributes = klass.attributes_builder.build_from_database(attributes, column_types)
-        klass.allocate.init_with('attributes' => attributes, 'new_record' => false)
+        klass.allocate.init_with("attributes" => attributes, "new_record" => false)
       end
 
       private
@@ -439,7 +439,7 @@ module ActiveRecord
           self.class.unscoped { self.class.find(id) }
         end
 
-      @attributes = fresh_object.instance_variable_get('@attributes')
+      @attributes = fresh_object.instance_variable_get("@attributes")
       @new_record = false
       self
     end
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
index f8dd35df0f..7b4b8c60f8 100644
--- a/activerecord/lib/active_record/querying.rb
+++ b/activerecord/lib/active_record/querying.rb
@@ -46,7 +46,7 @@ module ActiveRecord
         class_name: name
       }
 
-      message_bus.instrument('instantiation.active_record', payload) do
+      message_bus.instrument("instantiation.active_record", payload) do
         result_set.map { |record| instantiate(record, column_types) }
       end
     end
diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb
index 2c0ca62924..19bd1b8e65 100644
--- a/activerecord/lib/active_record/railtie.rb
+++ b/activerecord/lib/active_record/railtie.rb
@@ -17,10 +17,10 @@ module ActiveRecord
                                               :timestamps => true
 
     config.action_dispatch.rescue_responses.merge!(
-      'ActiveRecord::RecordNotFound'   => :not_found,
-      'ActiveRecord::StaleObjectError' => :conflict,
-      'ActiveRecord::RecordInvalid'    => :unprocessable_entity,
-      'ActiveRecord::RecordNotSaved'   => :unprocessable_entity
+      "ActiveRecord::RecordNotFound"   => :not_found,
+      "ActiveRecord::StaleObjectError" => :conflict,
+      "ActiveRecord::RecordInvalid"    => :unprocessable_entity,
+      "ActiveRecord::RecordNotSaved"   => :unprocessable_entity
     )
 
 
@@ -35,8 +35,8 @@ module ActiveRecord
           ActiveRecord::Tasks::DatabaseTasks.database_configuration = Rails.application.config.database_configuration
 
           if defined?(ENGINE_ROOT) && engine = Rails::Engine.find(ENGINE_ROOT)
-            if engine.paths['db/migrate'].existent
-              ActiveRecord::Tasks::DatabaseTasks.migrations_paths += engine.paths['db/migrate'].to_a
+            if engine.paths["db/migrate"].existent
+              ActiveRecord::Tasks::DatabaseTasks.migrations_paths += engine.paths["db/migrate"].to_a
             end
           end
         end
@@ -102,7 +102,7 @@ module ActiveRecord
     initializer "active_record.warn_on_records_fetched_greater_than" do
       if config.active_record.warn_on_records_fetched_greater_than
         ActiveSupport.on_load(:active_record) do
-          require 'active_record/relation/record_fetch_warning'
+          require "active_record/relation/record_fetch_warning"
         end
       end
     end
diff --git a/activerecord/lib/active_record/railties/controller_runtime.rb b/activerecord/lib/active_record/railties/controller_runtime.rb
index c13238cbe2..adb3c6c4e6 100644
--- a/activerecord/lib/active_record/railties/controller_runtime.rb
+++ b/activerecord/lib/active_record/railties/controller_runtime.rb
@@ -1,5 +1,5 @@
-require 'active_support/core_ext/module/attr_internal'
-require 'active_record/log_subscriber'
+require "active_support/core_ext/module/attr_internal"
+require "active_record/log_subscriber"
 
 module ActiveRecord
   module Railties # :nodoc:
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index fc1b62ee96..9481e5f7aa 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -1,4 +1,4 @@
-require 'active_record'
+require "active_record"
 
 db_namespace = namespace :db do
   desc "Set the environment value for the database"
@@ -22,7 +22,7 @@ db_namespace = namespace :db do
     end
   end
 
-  desc 'Creates the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:create:all to create all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to creating the development and test databases.'
+  desc "Creates the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:create:all to create all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to creating the development and test databases."
   task :create => [:load_config] do
     ActiveRecord::Tasks::DatabaseTasks.create_current
   end
@@ -33,7 +33,7 @@ db_namespace = namespace :db do
     end
   end
 
-  desc 'Drops the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to dropping the development and test databases.'
+  desc "Drops the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config). Without RAILS_ENV or when RAILS_ENV is development, it defaults to dropping the development and test databases."
   task :drop => [:load_config, :check_protected_environments] do
     db_namespace["drop:_unsafe"].invoke
   end
@@ -56,7 +56,7 @@ db_namespace = namespace :db do
   desc "Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)."
   task :migrate => [:environment, :load_config] do
     ActiveRecord::Tasks::DatabaseTasks.migrate
-    db_namespace['_dump'].invoke
+    db_namespace["_dump"].invoke
   end
 
   # IMPORTANT: This task won't dump the schema if ActiveRecord::Base.dump_schema_after_migration is set to false
@@ -71,44 +71,44 @@ db_namespace = namespace :db do
     end
     # Allow this task to be called as many times as required. An example is the
     # migrate:redo task, which calls other two internally that depend on this one.
-    db_namespace['_dump'].reenable
+    db_namespace["_dump"].reenable
   end
 
   namespace :migrate do
     # desc  'Rollbacks the database one migration and re migrate up (options: STEP=x, VERSION=x).'
     task :redo => [:environment, :load_config] do
-      if ENV['VERSION']
-        db_namespace['migrate:down'].invoke
-        db_namespace['migrate:up'].invoke
+      if ENV["VERSION"]
+        db_namespace["migrate:down"].invoke
+        db_namespace["migrate:up"].invoke
       else
-        db_namespace['rollback'].invoke
-        db_namespace['migrate'].invoke
+        db_namespace["rollback"].invoke
+        db_namespace["migrate"].invoke
       end
     end
 
     # desc 'Resets your database using your migrations for the current environment'
-    task :reset => ['db:drop', 'db:create', 'db:migrate']
+    task :reset => ["db:drop", "db:create", "db:migrate"]
 
     # desc 'Runs the "up" for a given migration VERSION.'
     task :up => [:environment, :load_config] do
-      version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
-      raise 'VERSION is required' unless version
+      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+      raise "VERSION is required" unless version
       ActiveRecord::Migrator.run(:up, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
-      db_namespace['_dump'].invoke
+      db_namespace["_dump"].invoke
     end
 
     # desc 'Runs the "down" for a given migration VERSION.'
     task :down => [:environment, :load_config] do
-      version = ENV['VERSION'] ? ENV['VERSION'].to_i : nil
-      raise 'VERSION is required - To go down one migration, run db:rollback' unless version
+      version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
+      raise "VERSION is required - To go down one migration, run db:rollback" unless version
       ActiveRecord::Migrator.run(:down, ActiveRecord::Tasks::DatabaseTasks.migrations_paths, version)
-      db_namespace['_dump'].invoke
+      db_namespace["_dump"].invoke
     end
 
-    desc 'Display status of migrations'
+    desc "Display status of migrations"
     task :status => [:environment, :load_config] do
       unless ActiveRecord::SchemaMigration.table_exists?
-        abort 'Schema migrations table does not exist yet.'
+        abort "Schema migrations table does not exist yet."
       end
       db_list = ActiveRecord::SchemaMigration.normalized_versions
 
@@ -119,13 +119,13 @@ db_namespace = namespace :db do
 
               version, name, scope = ActiveRecord::Migrator.parse_migration_filename(file)
               version = ActiveRecord::SchemaMigration.normalize_migration_number(version)
-              status = db_list.delete(version) ? 'up' : 'down'
+              status = db_list.delete(version) ? "up" : "down"
               [status, version, (name + scope).humanize]
             end.compact
           end
 
       db_list.map! do |version|
-        ['up', version, '********** NO FILE **********']
+        ["up", version, "********** NO FILE **********"]
       end
       # output
       puts "\ndatabase: #{ActiveRecord::Base.connection_config[:database]}\n\n"
@@ -138,22 +138,22 @@ db_namespace = namespace :db do
     end
   end
 
-  desc 'Rolls the schema back to the previous version (specify steps w/ STEP=n).'
+  desc "Rolls the schema back to the previous version (specify steps w/ STEP=n)."
   task :rollback => [:environment, :load_config] do
-    step = ENV['STEP'] ? ENV['STEP'].to_i : 1
+    step = ENV["STEP"] ? ENV["STEP"].to_i : 1
     ActiveRecord::Migrator.rollback(ActiveRecord::Tasks::DatabaseTasks.migrations_paths, step)
-    db_namespace['_dump'].invoke
+    db_namespace["_dump"].invoke
   end
 
   # desc 'Pushes the schema to the next version (specify steps w/ STEP=n).'
   task :forward => [:environment, :load_config] do
-    step = ENV['STEP'] ? ENV['STEP'].to_i : 1
+    step = ENV["STEP"] ? ENV["STEP"].to_i : 1
     ActiveRecord::Migrator.forward(ActiveRecord::Tasks::DatabaseTasks.migrations_paths, step)
-    db_namespace['_dump'].invoke
+    db_namespace["_dump"].invoke
   end
 
   # desc 'Drops and recreates the database from db/schema.rb for the current environment and loads the seeds.'
-  task :reset => [ 'db:drop', 'db:setup' ]
+  task :reset => [ "db:drop", "db:setup" ]
 
   # desc "Retrieves the charset for the current environment's database"
   task :charset => [:environment, :load_config] do
@@ -165,11 +165,11 @@ db_namespace = namespace :db do
     begin
       puts ActiveRecord::Tasks::DatabaseTasks.collation_current
     rescue NoMethodError
-      $stderr.puts 'Sorry, your database adapter is not supported yet. Feel free to submit a patch.'
+      $stderr.puts "Sorry, your database adapter is not supported yet. Feel free to submit a patch."
     end
   end
 
-  desc 'Retrieves the current schema version number'
+  desc "Retrieves the current schema version number"
   task :version => [:environment, :load_config] do
     puts "Current version: #{ActiveRecord::Migrator.current_version}"
   end
@@ -181,36 +181,36 @@ db_namespace = namespace :db do
     if pending_migrations.any?
       puts "You have #{pending_migrations.size} pending #{pending_migrations.size > 1 ? 'migrations:' : 'migration:'}"
       pending_migrations.each do |pending_migration|
-        puts '  %4d %s' % [pending_migration.version, pending_migration.name]
+        puts "  %4d %s" % [pending_migration.version, pending_migration.name]
       end
       abort %{Run `rails db:migrate` to update your database then try again.}
     end
   end
 
-  desc 'Creates the database, loads the schema, and initializes with the seed data (use db:reset to also drop the database first)'
-  task :setup => ['db:schema:load_if_ruby', 'db:structure:load_if_sql', :seed]
+  desc "Creates the database, loads the schema, and initializes with the seed data (use db:reset to also drop the database first)"
+  task :setup => ["db:schema:load_if_ruby", "db:structure:load_if_sql", :seed]
 
-  desc 'Loads the seed data from db/seeds.rb'
+  desc "Loads the seed data from db/seeds.rb"
   task :seed do
-    db_namespace['abort_if_pending_migrations'].invoke
+    db_namespace["abort_if_pending_migrations"].invoke
     ActiveRecord::Tasks::DatabaseTasks.load_seed
   end
 
   namespace :fixtures do
     desc "Loads fixtures into the current environment's database. Load specific fixtures using FIXTURES=x,y. Load from subdirectory in test/fixtures using FIXTURES_DIR=z. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
     task :load => [:environment, :load_config] do
-      require 'active_record/fixtures'
+      require "active_record/fixtures"
 
       base_dir = ActiveRecord::Tasks::DatabaseTasks.fixtures_path
 
-      fixtures_dir = if ENV['FIXTURES_DIR']
-                       File.join base_dir, ENV['FIXTURES_DIR']
+      fixtures_dir = if ENV["FIXTURES_DIR"]
+                       File.join base_dir, ENV["FIXTURES_DIR"]
                      else
                        base_dir
                      end
 
-      fixture_files = if ENV['FIXTURES']
-                        ENV['FIXTURES'].split(',')
+      fixture_files = if ENV["FIXTURES"]
+                        ENV["FIXTURES"].split(",")
                       else
                         # The use of String#[] here is to support namespaced fixtures
                         Dir["#{fixtures_dir}/**/*.yml"].map {|f| f[(fixtures_dir.size + 1)..-5] }
@@ -221,10 +221,10 @@ db_namespace = namespace :db do
 
     # desc "Search for a fixture given a LABEL or ID. Specify an alternative path (eg. spec/fixtures) using FIXTURES_PATH=spec/fixtures."
     task :identify => [:environment, :load_config] do
-      require 'active_record/fixtures'
+      require "active_record/fixtures"
 
-      label, id = ENV['LABEL'], ENV['ID']
-      raise 'LABEL or ID required' if label.blank? && id.blank?
+      label, id = ENV["LABEL"], ENV["ID"]
+      raise "LABEL or ID required" if label.blank? && id.blank?
 
       puts %Q(The fixture ID for "#{label}" is #{ActiveRecord::FixtureSet.identify(label)}.) if label
 
@@ -245,37 +245,37 @@ db_namespace = namespace :db do
   end
 
   namespace :schema do
-    desc 'Creates a db/schema.rb file that is portable against any DB supported by Active Record'
+    desc "Creates a db/schema.rb file that is portable against any DB supported by Active Record"
     task :dump => [:environment, :load_config] do
-      require 'active_record/schema_dumper'
-      filename = ENV['SCHEMA'] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, 'schema.rb')
+      require "active_record/schema_dumper"
+      filename = ENV["SCHEMA"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema.rb")
       File.open(filename, "w:utf-8") do |file|
         ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
       end
-      db_namespace['schema:dump'].reenable
+      db_namespace["schema:dump"].reenable
     end
 
-    desc 'Loads a schema.rb file into the database'
+    desc "Loads a schema.rb file into the database"
     task :load => [:environment, :load_config, :check_protected_environments] do
-      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:ruby, ENV['SCHEMA'])
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:ruby, ENV["SCHEMA"])
     end
 
-    task :load_if_ruby => ['db:create', :environment] do
+    task :load_if_ruby => ["db:create", :environment] do
       db_namespace["schema:load"].invoke if ActiveRecord::Base.schema_format == :ruby
     end
 
     namespace :cache do
-      desc 'Creates a db/schema_cache.dump file.'
+      desc "Creates a db/schema_cache.dump file."
       task :dump => [:environment, :load_config] do
         con = ActiveRecord::Base.connection
         filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.dump")
 
         con.schema_cache.clear!
         con.data_sources.each { |table| con.schema_cache.add(table) }
-        open(filename, 'wb') { |f| f.write(Marshal.dump(con.schema_cache)) }
+        open(filename, "wb") { |f| f.write(Marshal.dump(con.schema_cache)) }
       end
 
-      desc 'Clears a db/schema_cache.dump file.'
+      desc "Clears a db/schema_cache.dump file."
       task :clear => [:environment, :load_config] do
         filename = File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "schema_cache.dump")
         rm_f filename, verbose: false
@@ -285,9 +285,9 @@ db_namespace = namespace :db do
   end
 
   namespace :structure do
-    desc 'Dumps the database structure to db/structure.sql. Specify another file with SCHEMA=db/my_structure.sql'
+    desc "Dumps the database structure to db/structure.sql. Specify another file with SCHEMA=db/my_structure.sql"
     task :dump => [:environment, :load_config] do
-      filename = ENV['SCHEMA'] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "structure.sql")
+      filename = ENV["SCHEMA"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, "structure.sql")
       current_config = ActiveRecord::Tasks::DatabaseTasks.current_config
       ActiveRecord::Tasks::DatabaseTasks.structure_dump(current_config, filename)
 
@@ -298,15 +298,15 @@ db_namespace = namespace :db do
           f.print "\n"
         end
       end
-      db_namespace['structure:dump'].reenable
+      db_namespace["structure:dump"].reenable
     end
 
     desc "Recreates the databases from the structure.sql file"
     task :load => [:environment, :load_config, :check_protected_environments] do
-      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:sql, ENV['SCHEMA'])
+      ActiveRecord::Tasks::DatabaseTasks.load_schema_current(:sql, ENV["SCHEMA"])
     end
 
-    task :load_if_sql => ['db:create', :environment] do
+    task :load_if_sql => ["db:create", :environment] do
       db_namespace["structure:load"].invoke if ActiveRecord::Base.schema_format == :sql
     end
   end
@@ -335,7 +335,7 @@ db_namespace = namespace :db do
       begin
         should_reconnect = ActiveRecord::Base.connection_pool.active_connection?
         ActiveRecord::Schema.verbose = false
-        ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations['test'], :ruby, ENV['SCHEMA']
+        ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :ruby, ENV["SCHEMA"]
       ensure
         if should_reconnect
           ActiveRecord::Base.establish_connection(ActiveRecord::Base.configurations[ActiveRecord::Tasks::DatabaseTasks.env])
@@ -345,7 +345,7 @@ db_namespace = namespace :db do
 
     # desc "Recreate the test database from an existent structure.sql file"
     task :load_structure => %w(db:test:purge) do
-      ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations['test'], :sql, ENV['SCHEMA']
+      ActiveRecord::Tasks::DatabaseTasks.load_schema ActiveRecord::Base.configurations["test"], :sql, ENV["SCHEMA"]
     end
 
     # desc "Recreate the test database from a fresh schema"
@@ -366,13 +366,13 @@ db_namespace = namespace :db do
 
     # desc "Empty the test database"
     task :purge => %w(environment load_config check_protected_environments) do
-      ActiveRecord::Tasks::DatabaseTasks.purge ActiveRecord::Base.configurations['test']
+      ActiveRecord::Tasks::DatabaseTasks.purge ActiveRecord::Base.configurations["test"]
     end
 
     # desc 'Load the test schema'
     task :prepare => %w(environment load_config) do
       unless ActiveRecord::Base.configurations.blank?
-        db_namespace['test:load'].invoke
+        db_namespace["test:load"].invoke
       end
     end
   end
@@ -382,12 +382,12 @@ namespace :railties do
   namespace :install do
     # desc "Copies missing migrations from Railties (e.g. engines). You can specify Railties to use with FROM=railtie1,railtie2"
     task :migrations => :'db:load_config' do
-      to_load = ENV['FROM'].blank? ? :all : ENV['FROM'].split(",").map(&:strip)
+      to_load = ENV["FROM"].blank? ? :all : ENV["FROM"].split(",").map(&:strip)
       railties = {}
       Rails.application.migration_railties.each do |railtie|
         next unless to_load == :all || to_load.include?(railtie.railtie_name)
 
-        if railtie.respond_to?(:paths) && (path = railtie.paths['db/migrate'].first)
+        if railtie.respond_to?(:paths) && (path = railtie.paths["db/migrate"].first)
           railties[railtie.railtie_name] = path
         end
       end
diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index bf398b0d40..bd352d664d 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -1,5 +1,5 @@
-require 'thread'
-require 'active_support/core_ext/string/filters'
+require "thread"
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   # = Active Record Reflection
diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 0792ba8f76..e96adc9af8 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -62,7 +62,7 @@ module ActiveRecord
 
       @klass.connection.insert(
         im,
-        'SQL',
+        "SQL",
         primary_key || false,
         primary_key_value,
         nil,
@@ -86,7 +86,7 @@ module ActiveRecord
 
       @klass.connection.update(
         um,
-        'SQL',
+        "SQL",
         bvs,
       )
     end
@@ -382,7 +382,7 @@ module ActiveRecord
         stmt.wheres = arel.constraints
       end
 
-      @klass.connection.update stmt, 'SQL', bound_attributes
+      @klass.connection.update stmt, "SQL", bound_attributes
     end
 
     # Updates an object (or multiple objects) and saves it to the database, if validations pass.
@@ -533,7 +533,7 @@ module ActiveRecord
           stmt.wheres = arel.constraints
         end
 
-        affected = @klass.connection.delete(stmt, 'SQL', bound_attributes)
+        affected = @klass.connection.delete(stmt, "SQL", bound_attributes)
 
         reset
         affected
@@ -671,7 +671,7 @@ module ActiveRecord
 
     def inspect
       entries = records.take([limit_value, 11].compact.min).map!(&:inspect)
-      entries[10] = '...' if entries.size == 11
+      entries[10] = "..." if entries.size == 11
 
       "#<#{self.class.name} [#{entries.join(', ')}]>"
     end
@@ -726,7 +726,7 @@ module ActiveRecord
       return [] if string.blank?
       # always convert table names to downcase as in Oracle quoted table names are in uppercase
       # ignore raw_sql_ that is used by Oracle adapter as alias for limit/offset subqueries
-      string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map(&:downcase).uniq - ['raw_sql_']
+      string.scan(/([a-zA-Z_][.\w]+).?\./).flatten.map(&:downcase).uniq - ["raw_sql_"]
     end
   end
 end
diff --git a/activerecord/lib/active_record/relation/batches.rb b/activerecord/lib/active_record/relation/batches.rb
index 20ed4526b0..f4dd106edf 100644
--- a/activerecord/lib/active_record/relation/batches.rb
+++ b/activerecord/lib/active_record/relation/batches.rb
@@ -1,4 +1,4 @@
-require 'active_record/relation/batches/batch_enumerator'
+require "active_record/relation/batches/batch_enumerator"
 
 module ActiveRecord
   module Batches
diff --git a/activerecord/lib/active_record/relation/calculations.rb b/activerecord/lib/active_record/relation/calculations.rb
index a97b71815a..4af9f0859a 100644
--- a/activerecord/lib/active_record/relation/calculations.rb
+++ b/activerecord/lib/active_record/relation/calculations.rb
@@ -225,7 +225,7 @@ module ActiveRecord
     end
 
     def operation_over_aggregate_column(column, operation, distinct)
-      operation == 'count' ? column.count(distinct) : column.send(operation)
+      operation == "count" ? column.count(distinct) : column.send(operation)
     end
 
     def execute_simple_calculation(operation, column_name, distinct) #:nodoc:
@@ -276,10 +276,10 @@ module ActiveRecord
       group_aliases = group_fields.map { |field| column_alias_for(field) }
       group_columns = group_aliases.zip(group_fields)
 
-      if operation == 'count' && column_name == :all
-        aggregate_alias = 'count_all'
+      if operation == "count" && column_name == :all
+        aggregate_alias = "count_all"
       else
-        aggregate_alias = column_alias_for([operation, column_name].join(' '))
+        aggregate_alias = column_alias_for([operation, column_name].join(" "))
       end
 
       select_values = [
@@ -340,24 +340,24 @@ module ActiveRecord
       end
 
       table_name = keys.to_s.downcase
-      table_name.gsub!(/\*/, 'all')
-      table_name.gsub!(/\W+/, ' ')
+      table_name.gsub!(/\*/, "all")
+      table_name.gsub!(/\W+/, " ")
       table_name.strip!
-      table_name.gsub!(/ +/, '_')
+      table_name.gsub!(/ +/, "_")
 
       @klass.connection.table_alias_for(table_name)
     end
 
     def type_for(field, &block)
-      field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split('.').last
+      field_name = field.respond_to?(:name) ? field.name.to_s : field.to_s.split(".").last
       @klass.type_for_attribute(field_name, &block)
     end
 
     def type_cast_calculated_value(value, type, operation = nil)
       case operation
-        when 'count'   then value.to_i
-        when 'sum'     then type.deserialize(value || 0)
-        when 'average' then value.respond_to?(:to_d) ? value.to_d : value
+        when "count"   then value.to_i
+        when "sum"     then type.deserialize(value || 0)
+        when "average" then value.respond_to?(:to_d) ? value.to_d : value
         else type.deserialize(value)
       end
     end
@@ -372,15 +372,15 @@ module ActiveRecord
     end
 
     def build_count_subquery(relation, column_name, distinct)
-      column_alias = Arel.sql('count_column')
-      subquery_alias = Arel.sql('subquery_for_count')
+      column_alias = Arel.sql("count_column")
+      subquery_alias = Arel.sql("subquery_for_count")
 
       aliased_column = aggregate_column(column_name == :all ? 1 : column_name).as(column_alias)
       relation.select_values = [aliased_column]
       subquery = relation.arel.as(subquery_alias)
 
       sm = Arel::SelectManager.new relation.engine
-      select_value = operation_over_aggregate_column(column_alias, 'count', distinct)
+      select_value = operation_over_aggregate_column(column_alias, "count", distinct)
       sm.project(select_value).from(subquery)
     end
   end
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
index ad74659cba..2cb1df05df 100644
--- a/activerecord/lib/active_record/relation/delegation.rb
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -1,5 +1,5 @@
-require 'active_support/concern'
-require 'active_support/core_ext/regexp'
+require "active_support/concern"
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module Delegation # :nodoc:
@@ -18,7 +18,7 @@ module ActiveRecord
           delegate = Class.new(klass) {
             include ClassSpecificRelation
           }
-          const_set klass.name.gsub('::'.freeze, '_'.freeze), delegate
+          const_set klass.name.gsub("::".freeze, "_".freeze), delegate
           cache[klass] = delegate
         end
       end
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 916dca33bd..6241e0dbdb 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -1,8 +1,8 @@
-require 'active_support/core_ext/string/filters'
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   module FinderMethods
-    ONE_AS_ONE = '1 AS one'
+    ONE_AS_ONE = "1 AS one"
 
     # Find by id - This can either be a specific id (1), a list of ids (1, 5, 6), or an array of ids ([5, 6, 10]).
     # If one or more records can not be found for the requested ids, then RecordNotFound will be raised. If the primary key
@@ -388,7 +388,7 @@ module ActiveRecord
           []
         else
           arel = relation.arel
-          rows = connection.select_all(arel, 'SQL', relation.bound_attributes)
+          rows = connection.select_all(arel, "SQL", relation.bound_attributes)
           join_dependency.instantiate(rows, aliases)
         end
       end
@@ -425,7 +425,7 @@ module ActiveRecord
       relation = relation.except(:select).select(values).distinct!
       arel = relation.arel
 
-      id_rows = @klass.connection.select_all(arel, 'SQL', relation.bound_attributes)
+      id_rows = @klass.connection.select_all(arel, "SQL", relation.bound_attributes)
       id_rows.map {|row| row[primary_key]}
     end
 
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index 396638d74d..87a97803d5 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/hash/keys'
+require "active_support/core_ext/hash/keys"
 
 module ActiveRecord
   class Relation
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index e5496c02b2..8dbff84950 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -1,13 +1,13 @@
 module ActiveRecord
   class PredicateBuilder # :nodoc:
-    require 'active_record/relation/predicate_builder/array_handler'
-    require 'active_record/relation/predicate_builder/association_query_handler'
-    require 'active_record/relation/predicate_builder/base_handler'
-    require 'active_record/relation/predicate_builder/basic_object_handler'
-    require 'active_record/relation/predicate_builder/class_handler'
-    require 'active_record/relation/predicate_builder/polymorphic_array_handler'
-    require 'active_record/relation/predicate_builder/range_handler'
-    require 'active_record/relation/predicate_builder/relation_handler'
+    require "active_record/relation/predicate_builder/array_handler"
+    require "active_record/relation/predicate_builder/association_query_handler"
+    require "active_record/relation/predicate_builder/base_handler"
+    require "active_record/relation/predicate_builder/basic_object_handler"
+    require "active_record/relation/predicate_builder/class_handler"
+    require "active_record/relation/predicate_builder/polymorphic_array_handler"
+    require "active_record/relation/predicate_builder/range_handler"
+    require "active_record/relation/predicate_builder/relation_handler"
 
     delegate :resolve_column_aliases, to: :table
 
@@ -52,7 +52,7 @@ module ActiveRecord
           key
         else
           key = key.to_s
-          key.split('.'.freeze).first if key.include?('.'.freeze)
+          key.split(".".freeze).first if key.include?(".".freeze)
         end
       end.compact
     end
diff --git a/activerecord/lib/active_record/relation/query_attribute.rb b/activerecord/lib/active_record/relation/query_attribute.rb
index 7ba964e802..a68e508fcc 100644
--- a/activerecord/lib/active_record/relation/query_attribute.rb
+++ b/activerecord/lib/active_record/relation/query_attribute.rb
@@ -1,4 +1,4 @@
-require 'active_record/attribute'
+require "active_record/attribute"
 
 module ActiveRecord
   class Relation
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 0749bb30b5..3b86f1c605 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -2,9 +2,9 @@ require "active_record/relation/from_clause"
 require "active_record/relation/query_attribute"
 require "active_record/relation/where_clause"
 require "active_record/relation/where_clause_factory"
-require 'active_model/forbidden_attributes_protection'
-require 'active_support/core_ext/string/filters'
-require 'active_support/core_ext/regexp'
+require "active_model/forbidden_attributes_protection"
+require "active_support/core_ext/string/filters"
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module QueryMethods
@@ -271,7 +271,7 @@ module ActiveRecord
     #   # => ActiveModel::MissingAttributeError: missing attribute: other_field
     def select(*fields)
       return super if block_given?
-      raise ArgumentError, 'Call this with at least one field' if fields.empty?
+      raise ArgumentError, "Call this with at least one field" if fields.empty?
       spawn._select!(*fields)
     end
 
@@ -1014,7 +1014,7 @@ module ActiveRecord
       name = from_clause.name
       case opts
       when Relation
-        name ||= 'subquery'
+        name ||= "subquery"
         opts.arel.as(name.to_s)
       else
         opts
@@ -1027,7 +1027,7 @@ module ActiveRecord
         when Hash, Symbol, Array
           :association_join
         else
-          raise ArgumentError, 'only Hash, Symbol and Array are allowed'
+          raise ArgumentError, "only Hash, Symbol and Array are allowed"
         end
       end
 
@@ -1046,7 +1046,7 @@ module ActiveRecord
         when Arel::Nodes::Join
           :join_node
         else
-          raise 'unknown class: %s' % join.class.name
+          raise "unknown class: %s" % join.class.name
         end
       end
 
@@ -1125,9 +1125,9 @@ module ActiveRecord
           if does_not_support_reverse?(o)
             raise IrreversibleOrderError, "Order #{o.inspect} can not be reversed automatically"
           end
-          o.split(',').map! do |s|
+          o.split(",").map! do |s|
             s.strip!
-            s.gsub!(/\sasc\Z/i, ' DESC') || s.gsub!(/\sdesc\Z/i, ' ASC') || s.concat(' DESC')
+            s.gsub!(/\sasc\Z/i, " DESC") || s.gsub!(/\sdesc\Z/i, " ASC") || s.concat(" DESC")
           end
         else
           o
@@ -1150,7 +1150,7 @@ module ActiveRecord
     end
 
     VALID_DIRECTIONS = [:asc, :desc, :ASC, :DESC,
-                        'asc', 'desc', 'ASC', 'DESC'] # :nodoc:
+                        "asc", "desc", "ASC", "DESC"] # :nodoc:
 
     def validate_order_args(args)
       args.each do |arg|
diff --git a/activerecord/lib/active_record/relation/spawn_methods.rb b/activerecord/lib/active_record/relation/spawn_methods.rb
index d5c18a2a4a..619616c878 100644
--- a/activerecord/lib/active_record/relation/spawn_methods.rb
+++ b/activerecord/lib/active_record/relation/spawn_methods.rb
@@ -1,6 +1,6 @@
-require 'active_support/core_ext/hash/except'
-require 'active_support/core_ext/hash/slice'
-require 'active_record/relation/merger'
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/hash/slice"
+require "active_record/relation/merger"
 
 module ActiveRecord
   module SpawnMethods
diff --git a/activerecord/lib/active_record/relation/where_clause.rb b/activerecord/lib/active_record/relation/where_clause.rb
index 89396b518c..e1376ce00a 100644
--- a/activerecord/lib/active_record/relation/where_clause.rb
+++ b/activerecord/lib/active_record/relation/where_clause.rb
@@ -120,7 +120,7 @@ module ActiveRecord
       def invert_predicate(node)
         case node
         when NilClass
-          raise ArgumentError, 'Invalid argument for .where.not(), got nil.'
+          raise ArgumentError, "Invalid argument for .where.not(), got nil."
         when Arel::Nodes::In
           Arel::Nodes::NotIn.new(node.left, node.right)
         when Arel::Nodes::Equality
@@ -158,7 +158,7 @@ module ActiveRecord
         end
       end
 
-      ARRAY_WITH_EMPTY_STRING = ['']
+      ARRAY_WITH_EMPTY_STRING = [""]
       def non_empty_predicates
         predicates - ARRAY_WITH_EMPTY_STRING
       end
diff --git a/activerecord/lib/active_record/runtime_registry.rb b/activerecord/lib/active_record/runtime_registry.rb
index 9e86999c1b..b79eb2263f 100644
--- a/activerecord/lib/active_record/runtime_registry.rb
+++ b/activerecord/lib/active_record/runtime_registry.rb
@@ -1,4 +1,4 @@
-require 'active_support/per_thread_registry'
+require "active_support/per_thread_registry"
 
 module ActiveRecord
   # This is a thread locals registry for Active Record. For example:
diff --git a/activerecord/lib/active_record/sanitization.rb b/activerecord/lib/active_record/sanitization.rb
index f007e9e733..26679bb1c3 100644
--- a/activerecord/lib/active_record/sanitization.rb
+++ b/activerecord/lib/active_record/sanitization.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/regexp'
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module Sanitization
@@ -70,7 +70,7 @@ module ActiveRecord
       #   sanitize_sql_for_order("id ASC")
       #   # => "id ASC"
       def sanitize_sql_for_order(condition)
-        if condition.is_a?(Array) && condition.first.to_s.include?('?')
+        if condition.is_a?(Array) && condition.first.to_s.include?("?")
           sanitize_sql_array(condition)
         else
           condition
@@ -120,7 +120,7 @@ module ActiveRecord
         attrs.map do |attr, value|
           value = type_for_attribute(attr.to_s).serialize(value)
           "#{c.quote_table_name_for_assignment(table, attr)} = #{c.quote(value)}"
-        end.join(', ')
+        end.join(", ")
       end
 
       # Sanitizes a +string+ so that it is safe to use within an SQL
@@ -157,7 +157,7 @@ module ActiveRecord
         statement, *values = ary
         if values.first.is_a?(Hash) && /:\w+/.match?(statement)
           replace_named_bind_variables(statement, values.first)
-        elsif statement.include?('?')
+        elsif statement.include?("?")
           replace_bind_variables(statement, values)
         elsif statement.blank?
           statement
@@ -167,7 +167,7 @@ module ActiveRecord
       end
 
       def replace_bind_variables(statement, values) # :nodoc:
-        raise_if_bind_arity_mismatch(statement, statement.count('?'), values.size)
+        raise_if_bind_arity_mismatch(statement, statement.count("?"), values.size)
         bound = values.dup
         c = connection
         statement.gsub(/\?/) do
@@ -185,7 +185,7 @@ module ActiveRecord
 
       def replace_named_bind_variables(statement, bind_vars) # :nodoc:
         statement.gsub(/(:?):([a-zA-Z]\w*)/) do |match|
-          if $1 == ':' # skip postgresql casts
+          if $1 == ":" # skip postgresql casts
             match # return the whole match
           elsif bind_vars.include?(match = $2.to_sym)
             replace_bind_variable(bind_vars[match])
@@ -200,7 +200,7 @@ module ActiveRecord
           if value.respond_to?(:empty?) && value.empty?
             c.quote(nil)
           else
-            value.map { |v| c.quote(v) }.join(',')
+            value.map { |v| c.quote(v) }.join(",")
           end
         else
           c.quote(value)
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index cc3bb1cd06..5105088b2f 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -1,4 +1,4 @@
-require 'stringio'
+require "stringio"
 
 module ActiveRecord
   # = Active Record Schema Dumper
@@ -111,7 +111,7 @@ HEADER
 
           case pk
           when String
-            tbl.print ", primary_key: #{pk.inspect}" unless pk == 'id'
+            tbl.print ", primary_key: #{pk.inspect}" unless pk == "id"
             pkcol = columns.detect { |c| c.name == pk }
             pkcolspec = @connection.column_spec_for_primary_key(pkcol)
             if pkcolspec.present?
@@ -161,12 +161,12 @@ HEADER
           # add column type definition to our format string
           format_string.unshift "    t.%-#{type_length}s "
 
-          format_string *= ''
+          format_string *= ""
 
           column_specs.each do |colspec|
             values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
             values.unshift colspec[:type]
-            tbl.print((format_string % values).gsub(/,\s*$/, ''))
+            tbl.print((format_string % values).gsub(/,\s*$/, ""))
             tbl.puts
           end
 
@@ -213,7 +213,7 @@ HEADER
           index.columns.inspect,
           "name: #{index.name.inspect}",
         ]
-        index_parts << 'unique: true' if index.unique
+        index_parts << "unique: true" if index.unique
 
         index_lengths = (index.lengths || []).compact
         index_parts << "length: #{Hash[index.columns.zip(index.lengths)].inspect}" if index_lengths.any?
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
index b6cb233e03..99b23e5593 100644
--- a/activerecord/lib/active_record/schema_migration.rb
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -1,5 +1,5 @@
-require 'active_record/scoping/default'
-require 'active_record/scoping/named'
+require "active_record/scoping/default"
+require "active_record/scoping/named"
 
 module ActiveRecord
   # This class is used to create a table that keeps track of which migrations
diff --git a/activerecord/lib/active_record/scoping.rb b/activerecord/lib/active_record/scoping.rb
index 7794af8ca4..78231594d4 100644
--- a/activerecord/lib/active_record/scoping.rb
+++ b/activerecord/lib/active_record/scoping.rb
@@ -1,4 +1,4 @@
-require 'active_support/per_thread_registry'
+require "active_support/per_thread_registry"
 
 module ActiveRecord
   module Scoping
diff --git a/activerecord/lib/active_record/scoping/named.rb b/activerecord/lib/active_record/scoping/named.rb
index 5395bd6076..46ee3540bd 100644
--- a/activerecord/lib/active_record/scoping/named.rb
+++ b/activerecord/lib/active_record/scoping/named.rb
@@ -1,6 +1,6 @@
-require 'active_support/core_ext/array'
-require 'active_support/core_ext/hash/except'
-require 'active_support/core_ext/kernel/singleton_class'
+require "active_support/core_ext/array"
+require "active_support/core_ext/hash/except"
+require "active_support/core_ext/kernel/singleton_class"
 
 module ActiveRecord
   # = Active Record \Named \Scopes
@@ -142,7 +142,7 @@ module ActiveRecord
         #   Article.featured.titles
         def scope(name, body, &block)
           unless body.respond_to?(:call)
-            raise ArgumentError, 'The scope body needs to be callable.'
+            raise ArgumentError, "The scope body needs to be callable."
           end
 
           if dangerous_class_method?(name)
diff --git a/activerecord/lib/active_record/secure_token.rb b/activerecord/lib/active_record/secure_token.rb
index 8abda2ac49..2c412a45ed 100644
--- a/activerecord/lib/active_record/secure_token.rb
+++ b/activerecord/lib/active_record/secure_token.rb
@@ -25,7 +25,7 @@ module ActiveRecord
       # You're encouraged to add a unique index in the database to deal with this even more unlikely scenario.
       def has_secure_token(attribute = :token)
         # Load securerandom only when has_secure_token is used.
-        require 'active_support/core_ext/securerandom'
+        require "active_support/core_ext/securerandom"
         define_method("regenerate_#{attribute}") { update! attribute => self.class.generate_unique_secure_token }
         before_create { self.send("#{attribute}=", self.class.generate_unique_secure_token) unless self.send("#{attribute}?")}
       end
diff --git a/activerecord/lib/active_record/store.rb b/activerecord/lib/active_record/store.rb
index 1b407f7702..2169d64137 100644
--- a/activerecord/lib/active_record/store.rb
+++ b/activerecord/lib/active_record/store.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/hash/indifferent_access'
+require "active_support/core_ext/hash/indifferent_access"
 
 module ActiveRecord
   # Store gives you a thin wrapper around serialize for the purpose of storing hashes in a single column.
@@ -192,7 +192,7 @@ module ActiveRecord
       end
 
       def load(yaml)
-        self.class.as_indifferent_hash(@coder.load(yaml || ''))
+        self.class.as_indifferent_hash(@coder.load(yaml || ""))
       end
 
       def self.as_indifferent_hash(obj)
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index e3e665e149..52b4fcb742 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -1,4 +1,4 @@
-require 'active_support/core_ext/string/filters'
+require "active_support/core_ext/string/filters"
 
 module ActiveRecord
   module Tasks # :nodoc:
@@ -40,10 +40,10 @@ module ActiveRecord
       attr_writer :current_config, :db_dir, :migrations_paths, :fixtures_path, :root, :env, :seed_loader
       attr_accessor :database_configuration
 
-      LOCAL_HOSTS    = ['127.0.0.1', 'localhost']
+      LOCAL_HOSTS    = ["127.0.0.1", "localhost"]
 
       def check_protected_environments!
-        unless ENV['DISABLE_DATABASE_ENVIRONMENT_CHECK']
+        unless ENV["DISABLE_DATABASE_ENVIRONMENT_CHECK"]
           current = ActiveRecord::Migrator.current_environment
           stored  = ActiveRecord::Migrator.last_stored_environment
 
@@ -72,14 +72,14 @@ module ActiveRecord
       end
 
       def migrations_paths
-        @migrations_paths ||= Rails.application.paths['db/migrate'].to_a
+        @migrations_paths ||= Rails.application.paths["db/migrate"].to_a
       end
 
       def fixtures_path
-        @fixtures_path ||= if ENV['FIXTURES_PATH']
-                             File.join(root, ENV['FIXTURES_PATH'])
+        @fixtures_path ||= if ENV["FIXTURES_PATH"]
+                             File.join(root, ENV["FIXTURES_PATH"])
                            else
-                             File.join(root, 'test', 'fixtures')
+                             File.join(root, "test", "fixtures")
                            end
       end
 
@@ -106,7 +106,7 @@ module ActiveRecord
 
       def create(*arguments)
         configuration = arguments.first
-        class_for_adapter(configuration['adapter']).new(*arguments).create
+        class_for_adapter(configuration["adapter"]).new(*arguments).create
         $stdout.puts "Created database '#{configuration['database']}'"
       rescue DatabaseAlreadyExists
         $stderr.puts "Database '#{configuration['database']}' already exists"
@@ -133,7 +133,7 @@ module ActiveRecord
 
       def drop(*arguments)
         configuration = arguments.first
-        class_for_adapter(configuration['adapter']).new(*arguments).drop
+        class_for_adapter(configuration["adapter"]).new(*arguments).drop
         $stdout.puts "Dropped database '#{configuration['database']}'"
       rescue ActiveRecord::NoDatabaseError
         $stderr.puts "Database '#{configuration['database']}' does not exist"
@@ -156,7 +156,7 @@ module ActiveRecord
       def migrate
         verbose = ENV["VERBOSE"] ? ENV["VERBOSE"] == "true" : true
         version = ENV["VERSION"] ? ENV["VERSION"].to_i : nil
-        scope   = ENV['SCOPE']
+        scope   = ENV["SCOPE"]
         verbose_was, Migration.verbose = Migration.verbose, verbose
         Migrator.migrate(migrations_paths, version) do |migration|
           scope.blank? || scope == migration.scope
@@ -172,7 +172,7 @@ module ActiveRecord
 
       def charset(*arguments)
         configuration = arguments.first
-        class_for_adapter(configuration['adapter']).new(*arguments).charset
+        class_for_adapter(configuration["adapter"]).new(*arguments).charset
       end
 
       def collation_current(environment = env)
@@ -181,11 +181,11 @@ module ActiveRecord
 
       def collation(*arguments)
         configuration = arguments.first
-        class_for_adapter(configuration['adapter']).new(*arguments).collation
+        class_for_adapter(configuration["adapter"]).new(*arguments).collation
       end
 
       def purge(configuration)
-        class_for_adapter(configuration['adapter']).new(configuration).purge
+        class_for_adapter(configuration["adapter"]).new(configuration).purge
       end
 
       def purge_all
@@ -204,13 +204,13 @@ module ActiveRecord
       def structure_dump(*arguments)
         configuration = arguments.first
         filename = arguments.delete_at 1
-        class_for_adapter(configuration['adapter']).new(*arguments).structure_dump(filename)
+        class_for_adapter(configuration["adapter"]).new(*arguments).structure_dump(filename)
       end
 
       def structure_load(*arguments)
         configuration = arguments.first
         filename = arguments.delete_at 1
-        class_for_adapter(configuration['adapter']).new(*arguments).structure_load(filename)
+        class_for_adapter(configuration["adapter"]).new(*arguments).structure_load(filename)
       end
 
       def load_schema(configuration, format = ActiveRecord::Base.schema_format, file = nil) # :nodoc:
@@ -285,17 +285,17 @@ module ActiveRecord
 
       def each_current_configuration(environment)
         environments = [environment]
-        environments << 'test' if environment == 'development'
+        environments << "test" if environment == "development"
 
         configurations = ActiveRecord::Base.configurations.values_at(*environments)
         configurations.compact.each do |configuration|
-          yield configuration unless configuration['database'].blank?
+          yield configuration unless configuration["database"].blank?
         end
       end
 
       def each_local_configuration
         ActiveRecord::Base.configurations.each_value do |configuration|
-          next unless configuration['database']
+          next unless configuration["database"]
 
           if local_database?(configuration)
             yield configuration
@@ -306,7 +306,7 @@ module ActiveRecord
       end
 
       def local_database?(configuration)
-        configuration['host'].blank? || LOCAL_HOSTS.include?(configuration['host'])
+        configuration["host"].blank? || LOCAL_HOSTS.include?(configuration["host"])
       end
     end
   end
diff --git a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
index 8574807fd2..d10c1b05cd 100644
--- a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
@@ -11,7 +11,7 @@ module ActiveRecord
 
       def create
         establish_connection configuration_without_database
-        connection.create_database configuration['database'], creation_options
+        connection.create_database configuration["database"], creation_options
         establish_connection configuration
       rescue ActiveRecord::StatementInvalid => error
         if /database exists/ === error.message
@@ -23,26 +23,26 @@ module ActiveRecord
         if error.respond_to?(:errno) && error.errno == ACCESS_DENIED_ERROR
           $stdout.print error.message
           establish_connection root_configuration_without_database
-          connection.create_database configuration['database'], creation_options
-          if configuration['username'] != 'root'
-            connection.execute grant_statement.gsub(/\s+/, ' ').strip
+          connection.create_database configuration["database"], creation_options
+          if configuration["username"] != "root"
+            connection.execute grant_statement.gsub(/\s+/, " ").strip
           end
           establish_connection configuration
         else
           $stderr.puts error.inspect
           $stderr.puts "Couldn't create database for #{configuration.inspect}, #{creation_options.inspect}"
-          $stderr.puts "(If you set the charset manually, make sure you have a matching collation)" if configuration['encoding']
+          $stderr.puts "(If you set the charset manually, make sure you have a matching collation)" if configuration["encoding"]
         end
       end
 
       def drop
         establish_connection configuration
-        connection.drop_database configuration['database']
+        connection.drop_database configuration["database"]
       end
 
       def purge
         establish_connection configuration
-        connection.recreate_database configuration['database'], creation_options
+        connection.recreate_database configuration["database"], creation_options
       end
 
       def charset
@@ -61,15 +61,15 @@ module ActiveRecord
         args.concat(["--skip-comments"])
         args.concat(["#{configuration['database']}"])
 
-        run_cmd('mysqldump', args, 'dumping')
+        run_cmd("mysqldump", args, "dumping")
       end
 
       def structure_load(filename)
         args = prepare_command_options
-        args.concat(['--execute', %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}])
+        args.concat(["--execute", %{SET FOREIGN_KEY_CHECKS = 0; SOURCE #{filename}; SET FOREIGN_KEY_CHECKS = 1}])
         args.concat(["--database", "#{configuration['database']}"])
 
-        run_cmd('mysql', args, 'loading')
+        run_cmd("mysql", args, "loading")
       end
 
       private
@@ -79,19 +79,19 @@ module ActiveRecord
       end
 
       def configuration_without_database
-        configuration.merge('database' => nil)
+        configuration.merge("database" => nil)
       end
 
       def creation_options
         Hash.new.tap do |options|
-          options[:charset]     = configuration['encoding']   if configuration.include? 'encoding'
-          options[:collation]   = configuration['collation']  if configuration.include? 'collation'
+          options[:charset]     = configuration["encoding"]   if configuration.include? "encoding"
+          options[:collation]   = configuration["collation"]  if configuration.include? "collation"
         end
       end
 
       def error_class
-        if configuration['adapter'].include?('jdbc')
-          require 'active_record/railties/jdbcmysql_error'
+        if configuration["adapter"].include?("jdbc")
+          require "active_record/railties/jdbcmysql_error"
           ArJdbcMySQL::Error
         elsif defined?(Mysql2)
           Mysql2::Error
@@ -110,8 +110,8 @@ IDENTIFIED BY '#{configuration['password']}' WITH GRANT OPTION;
 
       def root_configuration_without_database
         configuration_without_database.merge(
-          'username' => 'root',
-          'password' => root_password
+          "username" => "root",
+          "password" => root_password
         )
       end
 
@@ -122,17 +122,17 @@ IDENTIFIED BY '#{configuration['password']}' WITH GRANT OPTION;
 
       def prepare_command_options
         args = {
-          'host'      => '--host',
-          'port'      => '--port',
-          'socket'    => '--socket',
-          'username'  => '--user',
-          'password'  => '--password',
-          'encoding'  => '--default-character-set',
-          'sslca'     => '--ssl-ca',
-          'sslcert'   => '--ssl-cert',
-          'sslcapath' => '--ssl-capath',
-          'sslcipher' => '--ssl-cipher',
-          'sslkey'    => '--ssl-key'
+          "host"      => "--host",
+          "port"      => "--port",
+          "socket"    => "--socket",
+          "username"  => "--user",
+          "password"  => "--password",
+          "encoding"  => "--default-character-set",
+          "sslca"     => "--ssl-ca",
+          "sslcert"   => "--ssl-cert",
+          "sslcapath" => "--ssl-capath",
+          "sslcipher" => "--ssl-cipher",
+          "sslkey"    => "--ssl-key"
         }.map { |opt, arg| "#{arg}=#{configuration[opt]}" if configuration[opt] }.compact
 
         args
diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
index b19ab57ee4..d290b12b73 100644
--- a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -1,8 +1,8 @@
 module ActiveRecord
   module Tasks # :nodoc:
     class PostgreSQLDatabaseTasks # :nodoc:
-      DEFAULT_ENCODING = ENV['CHARSET'] || 'utf8'
-      ON_ERROR_STOP_1 = 'ON_ERROR_STOP=1'.freeze
+      DEFAULT_ENCODING = ENV["CHARSET"] || "utf8"
+      ON_ERROR_STOP_1 = "ON_ERROR_STOP=1".freeze
 
       delegate :connection, :establish_connection, :clear_active_connections!,
         to: ActiveRecord::Base
@@ -13,8 +13,8 @@ module ActiveRecord
 
       def create(master_established = false)
         establish_master_connection unless master_established
-        connection.create_database configuration['database'],
-          configuration.merge('encoding' => encoding)
+        connection.create_database configuration["database"],
+          configuration.merge("encoding" => encoding)
         establish_connection configuration
       rescue ActiveRecord::StatementInvalid => error
         if /database .* already exists/ === error.message
@@ -26,7 +26,7 @@ module ActiveRecord
 
       def drop
         establish_master_connection
-        connection.drop_database configuration['database']
+        connection.drop_database configuration["database"]
       end
 
       def charset
@@ -48,28 +48,28 @@ module ActiveRecord
 
         search_path = case ActiveRecord::Base.dump_schemas
         when :schema_search_path
-          configuration['schema_search_path']
+          configuration["schema_search_path"]
         when :all
           nil
         when String
           ActiveRecord::Base.dump_schemas
         end
 
-        args = ['-s', '-x', '-O', '-f', filename]
+        args = ["-s", "-x", "-O", "-f", filename]
         unless search_path.blank?
-          args += search_path.split(',').map do |part|
+          args += search_path.split(",").map do |part|
             "--schema=#{part.strip}"
           end
         end
-        args << configuration['database']
-        run_cmd('pg_dump', args, 'dumping')
+        args << configuration["database"]
+        run_cmd("pg_dump", args, "dumping")
         File.open(filename, "a") { |f| f << "SET search_path TO #{connection.schema_search_path};\n\n" }
       end
 
       def structure_load(filename)
         set_psql_env
-        args = [ '-v', ON_ERROR_STOP_1, '-q', '-f', filename, configuration['database'] ]
-        run_cmd('psql', args, 'loading' )
+        args = [ "-v", ON_ERROR_STOP_1, "-q", "-f", filename, configuration["database"] ]
+        run_cmd("psql", args, "loading" )
       end
 
       private
@@ -79,21 +79,21 @@ module ActiveRecord
       end
 
       def encoding
-        configuration['encoding'] || DEFAULT_ENCODING
+        configuration["encoding"] || DEFAULT_ENCODING
       end
 
       def establish_master_connection
         establish_connection configuration.merge(
-          'database'           => 'postgres',
-          'schema_search_path' => 'public'
+          "database"           => "postgres",
+          "schema_search_path" => "public"
         )
       end
 
       def set_psql_env
-        ENV['PGHOST']     = configuration['host']          if configuration['host']
-        ENV['PGPORT']     = configuration['port'].to_s     if configuration['port']
-        ENV['PGPASSWORD'] = configuration['password'].to_s if configuration['password']
-        ENV['PGUSER']     = configuration['username'].to_s if configuration['username']
+        ENV["PGHOST"]     = configuration["host"]          if configuration["host"]
+        ENV["PGPORT"]     = configuration["port"].to_s     if configuration["port"]
+        ENV["PGPASSWORD"] = configuration["password"].to_s if configuration["password"]
+        ENV["PGUSER"]     = configuration["username"].to_s if configuration["username"]
       end
 
       def run_cmd(cmd, args, action)
diff --git a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
index 9ec3c8a94a..8533fb6aa5 100644
--- a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
@@ -8,15 +8,15 @@ module ActiveRecord
       end
 
       def create
-        raise DatabaseAlreadyExists if File.exist?(configuration['database'])
+        raise DatabaseAlreadyExists if File.exist?(configuration["database"])
 
         establish_connection configuration
         connection
       end
 
       def drop
-        require 'pathname'
-        path = Pathname.new configuration['database']
+        require "pathname"
+        path = Pathname.new configuration["database"]
         file = path.absolute? ? path.to_s : File.join(root, path)
 
         FileUtils.rm(file)
@@ -36,12 +36,12 @@ module ActiveRecord
       end
 
       def structure_dump(filename)
-        dbfile = configuration['database']
+        dbfile = configuration["database"]
         `sqlite3 #{dbfile} .schema > #{filename}`
       end
 
       def structure_load(filename)
-        dbfile = configuration['database']
+        dbfile = configuration["database"]
         `sqlite3 #{dbfile} < "#{filename}"`
       end
 
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 0ee1ebcfbe..a140dd236f 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -275,12 +275,12 @@ module ActiveRecord
       end
 
       def raise_in_transactional_callbacks
-        ActiveSupport::Deprecation.warn('ActiveRecord::Base.raise_in_transactional_callbacks is deprecated and will be removed without replacement.')
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.raise_in_transactional_callbacks is deprecated and will be removed without replacement.")
         true
       end
 
       def raise_in_transactional_callbacks=(value)
-        ActiveSupport::Deprecation.warn('ActiveRecord::Base.raise_in_transactional_callbacks= is deprecated, has no effect and will be removed without replacement.')
+        ActiveSupport::Deprecation.warn("ActiveRecord::Base.raise_in_transactional_callbacks= is deprecated, has no effect and will be removed without replacement.")
         value
       end
 
diff --git a/activerecord/lib/active_record/type.rb b/activerecord/lib/active_record/type.rb
index 4911d93dd9..1b2fc1b034 100644
--- a/activerecord/lib/active_record/type.rb
+++ b/activerecord/lib/active_record/type.rb
@@ -1,17 +1,17 @@
-require 'active_model/type'
+require "active_model/type"
 
-require 'active_record/type/internal/abstract_json'
-require 'active_record/type/internal/timezone'
+require "active_record/type/internal/abstract_json"
+require "active_record/type/internal/timezone"
 
-require 'active_record/type/date'
-require 'active_record/type/date_time'
-require 'active_record/type/time'
+require "active_record/type/date"
+require "active_record/type/date_time"
+require "active_record/type/time"
 
-require 'active_record/type/serialized'
-require 'active_record/type/adapter_specific_registry'
+require "active_record/type/serialized"
+require "active_record/type/adapter_specific_registry"
 
-require 'active_record/type/type_map'
-require 'active_record/type/hash_lookup_type_map'
+require "active_record/type/type_map"
+require "active_record/type/hash_lookup_type_map"
 
 module ActiveRecord
   module Type
diff --git a/activerecord/lib/active_record/type/adapter_specific_registry.rb b/activerecord/lib/active_record/type/adapter_specific_registry.rb
index d440eac619..208bc8def5 100644
--- a/activerecord/lib/active_record/type/adapter_specific_registry.rb
+++ b/activerecord/lib/active_record/type/adapter_specific_registry.rb
@@ -1,4 +1,4 @@
-require 'active_model/type/registry'
+require "active_model/type/registry"
 
 module ActiveRecord
   # :stopdoc:
diff --git a/activerecord/lib/active_record/type/type_map.rb b/activerecord/lib/active_record/type/type_map.rb
index 850a7a4e09..1f744ef115 100644
--- a/activerecord/lib/active_record/type/type_map.rb
+++ b/activerecord/lib/active_record/type/type_map.rb
@@ -1,4 +1,4 @@
-require 'concurrent/map'
+require "concurrent/map"
 
 module ActiveRecord
   module Type
diff --git a/activerecord/lib/active_record/type_caster.rb b/activerecord/lib/active_record/type_caster.rb
index accc339d00..f1686e4913 100644
--- a/activerecord/lib/active_record/type_caster.rb
+++ b/activerecord/lib/active_record/type_caster.rb
@@ -1,5 +1,5 @@
-require 'active_record/type_caster/map'
-require 'active_record/type_caster/connection'
+require "active_record/type_caster/map"
+require "active_record/type_caster/connection"
 
 module ActiveRecord
   module TypeCaster # :nodoc:
diff --git a/activerecord/lib/active_record/version.rb b/activerecord/lib/active_record/version.rb
index cf76a13b44..146cfacc18 100644
--- a/activerecord/lib/active_record/version.rb
+++ b/activerecord/lib/active_record/version.rb
@@ -1,4 +1,4 @@
-require_relative 'gem_version'
+require_relative "gem_version"
 
 module ActiveRecord
   # Returns the version of the currently loaded ActiveRecord as a <tt>Gem::Version</tt>
diff --git a/activerecord/lib/rails/generators/active_record.rb b/activerecord/lib/rails/generators/active_record.rb
index dc29213235..68fca44e3b 100644
--- a/activerecord/lib/rails/generators/active_record.rb
+++ b/activerecord/lib/rails/generators/active_record.rb
@@ -1,7 +1,7 @@
-require 'rails/generators/named_base'
-require 'rails/generators/active_model'
-require 'rails/generators/active_record/migration'
-require 'active_record'
+require "rails/generators/named_base"
+require "rails/generators/active_model"
+require "rails/generators/active_record/migration"
+require "active_record"
 
 module ActiveRecord
   module Generators # :nodoc:
diff --git a/activerecord/lib/rails/generators/active_record/migration.rb b/activerecord/lib/rails/generators/active_record/migration.rb
index c2b2209638..4263c11ffc 100644
--- a/activerecord/lib/rails/generators/active_record/migration.rb
+++ b/activerecord/lib/rails/generators/active_record/migration.rb
@@ -1,4 +1,4 @@
-require 'rails/generators/migration'
+require "rails/generators/migration"
 
 module ActiveRecord
   module Generators # :nodoc:
diff --git a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
index de03550ec2..253961071e 100644
--- a/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
+++ b/activerecord/lib/rails/generators/active_record/migration/migration_generator.rb
@@ -1,5 +1,5 @@
-require 'rails/generators/active_record'
-require 'active_support/core_ext/regexp'
+require "rails/generators/active_record"
+require "active_support/core_ext/regexp"
 
 module ActiveRecord
   module Generators # :nodoc:
@@ -28,7 +28,7 @@ module ActiveRecord
           @table_name       = normalize_table_name($2)
         when /join_table/
           if attributes.length == 2
-            @migration_action = 'join'
+            @migration_action = "join"
             @join_tables      = pluralize_table_names? ? attributes.map(&:plural_name) : attributes.map(&:singular_name)
 
             set_index_names
diff --git a/activerecord/lib/rails/generators/active_record/model/model_generator.rb b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
index 0d72913258..0d89b96ffd 100644
--- a/activerecord/lib/rails/generators/active_record/model/model_generator.rb
+++ b/activerecord/lib/rails/generators/active_record/model/model_generator.rb
@@ -1,4 +1,4 @@
-require 'rails/generators/active_record'
+require "rails/generators/active_record"
 
 module ActiveRecord
   module Generators # :nodoc:
@@ -22,13 +22,13 @@ module ActiveRecord
 
       def create_model_file
         generate_application_record
-        template 'model.rb', File.join('app/models', class_path, "#{file_name}.rb")
+        template "model.rb", File.join("app/models", class_path, "#{file_name}.rb")
       end
 
       def create_module_file
         return if regular_class_path.empty?
         generate_application_record
-        template 'module.rb', File.join('app/models', "#{class_path.join('/')}.rb") if behavior == :invoke
+        template "module.rb", File.join("app/models", "#{class_path.join('/')}.rb") if behavior == :invoke
       end
 
       hook_for :test_framework
@@ -42,13 +42,13 @@ module ActiveRecord
         # FIXME: Change this file to a symlink once RubyGems 2.5.0 is required.
         def generate_application_record
           if self.behavior == :invoke && !application_record_exist?
-            template 'application_record.rb', application_record_file_name
+            template "application_record.rb", application_record_file_name
           end
         end
 
         # Used by the migration template to determine the parent name of the model
         def parent_class_name
-          options[:parent] || 'ApplicationRecord'
+          options[:parent] || "ApplicationRecord"
         end
 
         def application_record_exist?
@@ -61,7 +61,7 @@ module ActiveRecord
           @application_record_file_name ||= if mountable_engine?
             "app/models/#{namespaced_path}/application_record.rb"
           else
-            'app/models/application_record.rb'
+            "app/models/application_record.rb"
           end
         end
     end