module ActiveRecord::Core

Attributes

strict_loading_mode[R]

Public Class Methods

configurations() click to toggle source

Returns fully resolved ActiveRecord::DatabaseConfigurations object

# File lib/active_record/core.rb, line 56
def self.configurations
  @@configurations
end
configurations=(config) click to toggle source

Contains the database configuration - as is typically stored in config/database.yml - as an ActiveRecord::DatabaseConfigurations object.

For example, the following database.yml…

development:
  adapter: sqlite3
  database: db/development.sqlite3

production:
  adapter: sqlite3
  database: db/production.sqlite3

…would result in ActiveRecord::Base.configurations to look like this:

#<ActiveRecord::DatabaseConfigurations:0x00007fd1acbdf800 @configurations=[
  #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbded10 @env_name="development",
    @name="primary", @config={adapter: "sqlite3", database: "db/development.sqlite3"}>,
  #<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fd1acbdea90 @env_name="production",
    @name="primary", @config={adapter: "sqlite3", database: "db/production.sqlite3"}>
]>
# File lib/active_record/core.rb, line 50
def self.configurations=(config)
  @@configurations = ActiveRecord::DatabaseConfigurations.new(config)
end
connection_handler() click to toggle source
# File lib/active_record/core.rb, line 94
def self.connection_handler
  ActiveSupport::IsolatedExecutionState[:active_record_connection_handler] || default_connection_handler
end
connection_handler=(handler) click to toggle source
# File lib/active_record/core.rb, line 98
def self.connection_handler=(handler)
  ActiveSupport::IsolatedExecutionState[:active_record_connection_handler] = handler
end
connection_handlers() click to toggle source
# File lib/active_record/core.rb, line 102
def self.connection_handlers
  if ActiveRecord.legacy_connection_handling
  else
    raise NotImplementedError, "The new connection handling does not support accessing multiple connection handlers."
  end

  @@connection_handlers ||= {}
end
connection_handlers=(handlers) click to toggle source
# File lib/active_record/core.rb, line 111
      def self.connection_handlers=(handlers)
        if ActiveRecord.legacy_connection_handling
          ActiveSupport::Deprecation.warn(<<~MSG)
            Using legacy connection handling is deprecated. Please set
            `legacy_connection_handling` to `false` in your application.

            The new connection handling does not support `connection_handlers`
            getter and setter.

            Read more about how to migrate at: https://guides.rubyonrails.org/active_record_multiple_databases.html#migrate-to-the-new-connection-handling
          MSG
        else
          raise NotImplementedError, "The new connection handling does not support multiple connection handlers."
        end

        @@connection_handlers = handlers
      end
current_preventing_writes() click to toggle source

Returns the symbol representing the current setting for preventing writes.

ActiveRecord::Base.connected_to(role: :reading) do
  ActiveRecord::Base.current_preventing_writes #=> true
end

ActiveRecord::Base.connected_to(role: :writing) do
  ActiveRecord::Base.current_preventing_writes #=> false
end
# File lib/active_record/core.rb, line 188
def self.current_preventing_writes
  if ActiveRecord.legacy_connection_handling
    connection_handler.prevent_writes
  else
    connected_to_stack.reverse_each do |hash|
      return hash[:prevent_writes] if !hash[:prevent_writes].nil? && hash[:klasses].include?(Base)
      return hash[:prevent_writes] if !hash[:prevent_writes].nil? && hash[:klasses].include?(connection_class_for_self)
    end

    false
  end
end
current_role() click to toggle source

Returns the symbol representing the current connected role.

ActiveRecord::Base.connected_to(role: :writing) do
  ActiveRecord::Base.current_role #=> :writing
end

ActiveRecord::Base.connected_to(role: :reading) do
  ActiveRecord::Base.current_role #=> :reading
end
# File lib/active_record/core.rb, line 147
def self.current_role
  if ActiveRecord.legacy_connection_handling
    connection_handlers.key(connection_handler) || default_role
  else
    connected_to_stack.reverse_each do |hash|
      return hash[:role] if hash[:role] && hash[:klasses].include?(Base)
      return hash[:role] if hash[:role] && hash[:klasses].include?(connection_class_for_self)
    end

    default_role
  end
end
current_shard() click to toggle source

Returns the symbol representing the current connected shard.

ActiveRecord::Base.connected_to(role: :reading) do
  ActiveRecord::Base.current_shard #=> :default
end

ActiveRecord::Base.connected_to(role: :writing, shard: :one) do
  ActiveRecord::Base.current_shard #=> :one
end
# File lib/active_record/core.rb, line 169
def self.current_shard
  connected_to_stack.reverse_each do |hash|
    return hash[:shard] if hash[:shard] && hash[:klasses].include?(Base)
    return hash[:shard] if hash[:shard] && hash[:klasses].include?(connection_class_for_self)
  end

  default_shard
end
destroy_association_async_job() click to toggle source

Specifies the job used to destroy associations in the background

# File lib/active_record/core.rb, line 26
class_attribute :destroy_association_async_job, instance_writer: false, instance_predicate: false, default: false
enumerate_columns_in_select_statements() click to toggle source

Force enumeration of all columns in SELECT statements. e.g. ‘SELECT first_name, last_name FROM …` instead of `SELECT * FROM …` This avoids PreparedStatementCacheExpired errors when a column is added to the database while the app is running.

# File lib/active_record/core.rb, line 66
class_attribute :enumerate_columns_in_select_statements, instance_accessor: false, default: false
logger() click to toggle source

Accepts a logger conforming to the interface of Log4r which is then passed on to any new database connections made and which can be retrieved on both a class and instance level by calling logger.

# File lib/active_record/core.rb, line 20
class_attribute :logger, instance_writer: false
new(attributes = nil) { |self| ... } click to toggle source

New objects can be instantiated as either empty (pass no construction parameter) or pre-set with attributes but not yet saved (pass a hash with key names matching the associated table column names). In both instances, valid attribute keys are determined by the column names of the associated table – hence you can’t have attributes that aren’t part of the table columns.

Example:

# Instantiates a single new object
User.new(first_name: 'Jamie')
# File lib/active_record/core.rb, line 461
def initialize(attributes = nil)
  @new_record = true
  @attributes = self.class._default_attributes.deep_dup

  init_internals
  initialize_internals_callback

  assign_attributes(attributes) if attributes

  yield self if block_given?
  _run_initialize_callbacks
end

Public Instance Methods

<=>(other_object) click to toggle source

Allows sort on objects

Calls superclass method
# File lib/active_record/core.rb, line 614
def <=>(other_object)
  if other_object.is_a?(self.class)
    to_key <=> other_object.to_key
  else
    super
  end
end
==(comparison_object) click to toggle source

Returns true if comparison_object is the same exact object, or comparison_object is of the same type and self has an ID and it is equal to comparison_object.id.

Note that new records are different from any other record by definition, unless the other record is the receiver itself. Besides, if you fetch existing records with select and leave the ID out, you’re on your own, this predicate will return false.

Note also that destroying a record preserves its ID in the model instance, so deleted models are still comparable.

Calls superclass method
# File lib/active_record/core.rb, line 580
def ==(comparison_object)
  super ||
    comparison_object.instance_of?(self.class) &&
    !id.nil? &&
    comparison_object.id == id
end
Also aliased as: eql?
clone() click to toggle source

Identical to Ruby’s clone method. This is a “shallow” copy. Be warned that your attributes are not copied. That means that modifying attributes of the clone will modify the original, since they will both point to the same attributes hash. If you need a copy of your attributes hash, please use the dup method.

user = User.first
new_user = user.clone
user.name               # => "Bob"
new_user.name = "Joe"
user.name               # => "Joe"

user.object_id == new_user.object_id            # => false
user.name.object_id == new_user.name.object_id  # => true

user.name.object_id == user.dup.name.object_id  # => false
# File lib/active_record/core.rb, line 513
    
connection_handler() click to toggle source
# File lib/active_record/core.rb, line 682
def connection_handler
  self.class.connection_handler
end
dup() click to toggle source

Duped objects have no id assigned and are treated as new records. Note that this is a “shallow” copy as it copies the object’s attributes only, not its associations. The extent of a “deep” copy is application specific and is therefore left to the application to implement according to its need. The dup method does not preserve the timestamps (created|updated)_(at|on).

# File lib/active_record/core.rb, line 530
    
encode_with(coder) click to toggle source

Populate coder with attributes about this record that should be serialized. The structure of coder defined in this method is guaranteed to match the structure of coder passed to the init_with method.

Example:

class Post < ActiveRecord::Base
end
coder = {}
Post.new.encode_with(coder)
coder # => {"attributes" => {"id" => nil, ... }}
# File lib/active_record/core.rb, line 565
def encode_with(coder)
  self.class.yaml_encoder.encode(@attributes, coder)
  coder["new_record"] = new_record?
  coder["active_record_yaml_version"] = 2
end
eql?(comparison_object)
Alias for: ==
freeze() click to toggle source

Clone and freeze the attributes hash such that associations are still accessible, even on destroyed records, but cloned models will not be frozen.

# File lib/active_record/core.rb, line 603
def freeze
  @attributes = @attributes.clone.freeze
  self
end
frozen?() click to toggle source

Returns true if the attributes hash has been frozen.

# File lib/active_record/core.rb, line 609
def frozen?
  @attributes.frozen?
end
hash() click to toggle source

Delegates to id in order to allow two records of the same type and id to work with something like:

[ Person.find(1), Person.find(2), Person.find(3) ] & [ Person.find(1), Person.find(4) ] # => [ Person.find(1) ]
Calls superclass method
# File lib/active_record/core.rb, line 590
def hash
  id = self.id

  if id
    self.class.hash ^ id.hash
  else
    super
  end
end
init_with(coder, &block) click to toggle source

Initialize an empty model object from coder. coder should be the result of previously encoding an Active Record model, using encode_with.

class Post < ActiveRecord::Base
end

old_post = Post.new(title: "hello world")
coder = {}
old_post.encode_with(coder)

post = Post.allocate
post.init_with(coder)
post.title # => 'hello world'
# File lib/active_record/core.rb, line 488
def init_with(coder, &block)
  coder = LegacyYamlAdapter.convert(coder)
  attributes = self.class.yaml_encoder.decode(coder)
  init_with_attributes(attributes, coder["new_record"], &block)
end
inspect() click to toggle source

Returns the contents of the record as a nicely formatted string.

# File lib/active_record/core.rb, line 687
def inspect
  # We check defined?(@attributes) not to issue warnings if the object is
  # allocated but not initialized.
  inspection = if defined?(@attributes) && @attributes
    self.class.attribute_names.filter_map do |name|
      if _has_attribute?(name)
        "#{name}: #{attribute_for_inspect(name)}"
      end
    end.join(", ")
  else
    "not initialized"
  end

  "#<#{self.class} #{inspection}>"
end
pretty_print(pp) click to toggle source

Takes a PP and prettily prints this record to it, allowing you to get a nice result from pp record when pp is required.

Calls superclass method
# File lib/active_record/core.rb, line 705
def pretty_print(pp)
  return super if custom_inspect_method_defined?
  pp.object_address_group(self) do
    if defined?(@attributes) && @attributes
      attr_names = self.class.attribute_names.select { |name| _has_attribute?(name) }
      pp.seplist(attr_names, proc { pp.text "," }) do |attr_name|
        pp.breakable " "
        pp.group(1) do
          pp.text attr_name
          pp.text ":"
          pp.breakable
          value = _read_attribute(attr_name)
          value = inspection_filter.filter_param(attr_name, value) unless value.nil?
          pp.pp value
        end
      end
    else
      pp.breakable " "
      pp.text "not initialized"
    end
  end
end
readonly!() click to toggle source

Marks this record as read only.

# File lib/active_record/core.rb, line 678
def readonly!
  @readonly = true
end
readonly?() click to toggle source

Returns true if the record is read only.

# File lib/active_record/core.rb, line 631
def readonly?
  @readonly
end
slice(*methods) click to toggle source

Returns a hash of the given methods with their names as keys and returned values as values.

# File lib/active_record/core.rb, line 729
def slice(*methods)
  methods.flatten.index_with { |method| public_send(method) }.with_indifferent_access
end
strict_loading!(value = true, mode: :all) click to toggle source

Sets the record to strict_loading mode. This will raise an error if the record tries to lazily load an association.

user = User.first
user.strict_loading! # => true
user.comments
=> ActiveRecord::StrictLoadingViolationError

Parameters:

  • value - Boolean specifying whether to enable or disable strict loading.

  • mode - Symbol specifying strict loading mode. Defaults to :all. Using

    :n_plus_one_only mode will only raise an error if an association
    that will lead to an n plus one query is lazily loaded.

Example:

user = User.first
user.strict_loading!(false) # => false
user.comments
=> #<ActiveRecord::Associations::CollectionProxy>
# File lib/active_record/core.rb, line 661
def strict_loading!(value = true, mode: :all)
  unless [:all, :n_plus_one_only].include?(mode)
    raise ArgumentError, "The :mode option must be one of [:all, :n_plus_one_only]."
  end

  @strict_loading_mode = mode
  @strict_loading = value
end
strict_loading?() click to toggle source

Returns true if the record is in strict_loading mode.

# File lib/active_record/core.rb, line 636
def strict_loading?
  @strict_loading
end
strict_loading_n_plus_one_only?() click to toggle source

Returns true if the record uses strict_loading with :n_plus_one_only mode enabled.

# File lib/active_record/core.rb, line 673
def strict_loading_n_plus_one_only?
  @strict_loading_mode == :n_plus_one_only
end
values_at(*methods) click to toggle source

Returns an array of the values returned by the given methods.

# File lib/active_record/core.rb, line 734
def values_at(*methods)
  methods.flatten.map! { |method| public_send(method) }
end

Private Instance Methods

custom_inspect_method_defined?() click to toggle source
# File lib/active_record/core.rb, line 771
def custom_inspect_method_defined?
  self.class.instance_method(:inspect).owner != ActiveRecord::Base.instance_method(:inspect).owner
end
init_internals() click to toggle source
# File lib/active_record/core.rb, line 751
def init_internals
  @readonly                 = false
  @previously_new_record    = false
  @destroyed                = false
  @marked_for_destruction   = false
  @destroyed_by_association = nil
  @_start_transaction_state = nil

  klass = self.class

  @primary_key         = klass.primary_key
  @strict_loading      = klass.strict_loading_by_default
  @strict_loading_mode = :all

  klass.define_attribute_methods
end
initialize_internals_callback() click to toggle source
# File lib/active_record/core.rb, line 768
def initialize_internals_callback
end
inspection_filter() click to toggle source
# File lib/active_record/core.rb, line 782
def inspection_filter
  self.class.inspection_filter
end
to_ary() click to toggle source

+Array#flatten+ will call #to_ary (recursively) on each of the elements of the array, and then rescues from the possible NoMethodError. If those elements are ActiveRecord::Base‘s, then this triggers the various method_missing’s that we have, which significantly impacts upon performance.

So we can avoid the method_missing hit by explicitly defining #to_ary as nil here.

See also tenderlovemaking.com/2011/06/28/til-its-ok-to-return-nil-from-to_ary.html

# File lib/active_record/core.rb, line 747
def to_ary
  nil
end