# module ActiveRecord::Core

### Public Class Methods

configurations() click to toggle source

Returns fully resolved configurations hash

    # File lib/active_record/core.rb, line 51
    def self.configurations
      @@configurations
    end

configurations=(config) click to toggle source

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 lib/active_record/core.rb, line 45
    def self.configurations=(config)
      @@configurations = ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
    end

connection_handler() click to toggle source

    # File lib/active_record/core.rb, line 141
    def self.connection_handler
      ActiveRecord::RuntimeRegistry.connection_handler || default_connection_handler
    end

connection_handler=(handler) click to toggle source

    # File lib/active_record/core.rb, line 145
    def self.connection_handler=(handler)
      ActiveRecord::RuntimeRegistry.connection_handler = handler
    end

error_on_ignored_order_or_limit() click to toggle source

    # File lib/active_record/core.rb, line 81
          def self.error_on_ignored_order_or_limit
            ActiveSupport::Deprecation.warn("          The flag error_on_ignored_order_or_limit is deprecated. Limits are
              now supported. Please use error_on_ignored_order instead.
    ".squish)
            error_on_ignored_order
          end

error_on_ignored_order_or_limit=(value) click to toggle source

    # File lib/active_record/core.rb, line 93
          def self.error_on_ignored_order_or_limit=(value)
            ActiveSupport::Deprecation.warn("          The flag error_on_ignored_order_or_limit is deprecated. Limits are
              now supported. Please use error_on_ignored_order= instead.
    ".squish)
            self.error_on_ignored_order = value
          end

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 330
    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

### Public Instance Methods

<=>(other_object) click to toggle source

Allows sort on objects

Calls superclass method

    # File lib/active_record/core.rb, line 473
    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 441
    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 392

connection_handler() click to toggle source

    # File lib/active_record/core.rb, line 492
    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 401

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 426
    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: ==
error_on_ignored_order_or_limit() click to toggle source

    # File lib/active_record/core.rb, line 89
    def error_on_ignored_order_or_limit
      self.class.error_on_ignored_order_or_limit
    end

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 462
    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 468
    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 451
    def hash
      if id
        self.class.hash ^ id.hash
      else
        super
      end
    end

init_with(coder) { |self| ... } 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 357
    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() click to toggle source

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

    # File lib/active_record/core.rb, line 497
    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) 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 515
    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!() click to toggle source

Marks this record as read only.

    # File lib/active_record/core.rb, line 488
    def readonly!
      @readonly = true
    end

readonly?() click to toggle source

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 lib/active_record/core.rb, line 483
    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 538
    def slice(*methods)
      Hash[methods.flatten.map! { |method| [method, public_send(method)] }].with_indifferent_access
    end

### Private Instance Methods

custom_inspect_method_defined?() click to toggle source

    # File lib/active_record/core.rb, line 575
    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 556
    def init_internals
      @readonly                 = false
      @destroyed                = false
      @marked_for_destruction   = false
      @destroyed_by_association = nil
      @new_record               = true
      @_start_transaction_state = {}
      @transaction_state        = nil
    end

initialize_internals_callback() click to toggle source

    # File lib/active_record/core.rb, line 566
    def initialize_internals_callback
    end

thaw() click to toggle source

    # File lib/active_record/core.rb, line 569
    def thaw
      if frozen?
        @attributes = @attributes.dup
      end
    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 552
    def to_ary
      nil
    end