Methods
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Class Public methods
configurations()

Returns fully resolved configurations hash

# File activerecord/lib/active_record/core.rb, line 59
def self.configurations
  @@configurations
end
configurations=(config)

Contains the database configuration - as is typically stored in config/database.yml - as a Hash.

For example, the following database.yml…

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

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

…would result in ::configurations to look like this:

{
   'development' => {
      'adapter'  => 'sqlite3',
      'database' => 'db/development.sqlite3'
   },
   'production' => {
      'adapter'  => 'sqlite3',
      'database' => 'db/production.sqlite3'
   }
}
# File activerecord/lib/active_record/core.rb, line 53
def self.configurations=(config)
  @@configurations = ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
end
connection_handler()
# File activerecord/lib/active_record/core.rb, line 130
def self.connection_handler
  ActiveRecord::RuntimeRegistry.connection_handler || default_connection_handler
end
connection_handler=(handler)
# File activerecord/lib/active_record/core.rb, line 134
def self.connection_handler=(handler)
  ActiveRecord::RuntimeRegistry.connection_handler = handler
end
new(attributes = nil)

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 activerecord/lib/active_record/core.rb, line 307
def initialize(attributes = nil)
  self.class.define_attribute_methods
  @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
Instance Public methods
<=>(other_object)

Allows sort on objects

# File activerecord/lib/active_record/core.rb, line 452
def <=>(other_object)
  if other_object.is_a?(self.class)
    to_key <=> other_object.to_key
  else
    super
  end
end
==(comparison_object)

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.

Also aliased as: eql?
# File activerecord/lib/active_record/core.rb, line 420
def ==(comparison_object)
  super ||
    comparison_object.instance_of?(self.class) &&
    !id.nil? &&
    comparison_object.id == id
end
clone

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 activerecord/lib/active_record/core.rb, line 369
    
connection_handler()
# File activerecord/lib/active_record/core.rb, line 471
def connection_handler
  self.class.connection_handler
end
dup

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 activerecord/lib/active_record/core.rb, line 378
    
encode_with(coder)

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 activerecord/lib/active_record/core.rb, line 405
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()

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

# File activerecord/lib/active_record/core.rb, line 441
def freeze
  @attributes = @attributes.clone.freeze
  self
end
frozen?()

Returns true if the attributes hash has been frozen.

# File activerecord/lib/active_record/core.rb, line 447
def frozen?
  @attributes.frozen?
end
hash()

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) ]
# File activerecord/lib/active_record/core.rb, line 430
def hash
  if id
    self.class.hash ^ id.hash
  else
    super
  end
end
init_with(coder)

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 activerecord/lib/active_record/core.rb, line 334
def init_with(coder)
  coder = LegacyYamlAdapter.convert(self.class, coder)
  @attributes = self.class.yaml_encoder.decode(coder)

  init_internals

  @new_record = coder["new_record"]

  self.class.define_attribute_methods

  yield self if block_given?

  _run_find_callbacks
  _run_initialize_callbacks

  self
end
inspect()

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

# File activerecord/lib/active_record/core.rb, line 476
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.collect do |name|
      if has_attribute?(name)
        "#{name}: #{attribute_for_inspect(name)}"
      end
    end.compact.join(", ")
  else
    "not initialized"
  end

  "#<#{self.class} #{inspection}>"
end
pretty_print(pp)

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

# File activerecord/lib/active_record/core.rb, line 494
def pretty_print(pp)
  return super if custom_inspect_method_defined?
  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|
        column_value = read_attribute(column_name)
        pp.breakable " "
        pp.group(1) do
          pp.text column_name
          pp.text ":"
          pp.breakable
          pp.pp column_value
        end
      end
    else
      pp.breakable " "
      pp.text "not initialized"
    end
  end
end
readonly!()

Marks this record as read only.

# File activerecord/lib/active_record/core.rb, line 467
def readonly!
  @readonly = true
end
readonly?()

Returns true if the record is read only. Records loaded through joins with piggy-back attributes will be marked as read only since they cannot be saved.

# File activerecord/lib/active_record/core.rb, line 462
def readonly?
  @readonly
end
slice(*methods)

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

# File activerecord/lib/active_record/core.rb, line 517
def slice(*methods)
  Hash[methods.flatten.map! { |method| [method, public_send(method)] }].with_indifferent_access
end