module ActiveRecord::Core - activerecord-4.2.4 Documentation

# 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 100
    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 104
    def self.connection_handler=(handler)
      ActiveRecord::RuntimeRegistry.connection_handler = handler
    end

disable_implicit_join_references=(value) click to toggle source

    # File lib/active_record/core.rb, line 90
          def self.disable_implicit_join_references=(value)
            ActiveSupport::Deprecation.warn("          Implicit join references were removed with Rails 4.1.
              Make sure to remove this configuration because it does nothing.
    ".squish)
          end

new(attributes = nil, options = {}) { |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 272
    def initialize(attributes = nil, options = {})
      @attributes = self.class._default_attributes.dup
      self.class.define_attribute_methods

      init_internals
      initialize_internals_callback

      # +options+ argument is only needed to make protected_attributes gem easier to hook.
      # Remove it when we drop support to this gem.
      init_attributes(attributes, options) 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 418
    def <=>(other_object)
      if other_object.is_a?(self.class)
        self.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 386
    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 333

connection_handler() click to toggle source

    # File lib/active_record/core.rb, line 437
    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 342

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 370
    def encode_with(coder)
      # FIXME: Remove this when we better serialize attributes
      coder['raw_attributes'] = attributes_before_type_cast
      coder['attributes'] = @attributes
      coder['new_record'] = new_record?
    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 407
    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 413
    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 396
    def hash
      if id
        id.hash
      else
        super
      end
    end

init_with(coder) 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 301
    def init_with(coder)
      @attributes = coder['attributes']

      init_internals

      @new_record = coder['new_record']

      self.class.define_attribute_methods

      _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 442
    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.column_names.collect { |name|
                       if has_attribute?(name)
                         "#{name}: #{attribute_for_inspect(name)}"
                       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 459
    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 433
    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 428
    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 482
    def slice(*methods)
      Hash[methods.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 573
    def custom_inspect_method_defined?
      self.class.instance_method(:inspect).owner != ActiveRecord::Base.instance_method(:inspect).owner
    end

init_attributes(attributes, options) click to toggle source

This method is needed to make protected_attributes gem easier to hook. Remove it when we drop support to this gem.

    # File lib/active_record/core.rb, line 563
    def init_attributes(attributes, options)
      assign_attributes(attributes)
    end

init_internals() click to toggle source

    # File lib/active_record/core.rb, line 545
    def init_internals
      @aggregation_cache        = {}
      @association_cache        = {}
      @readonly                 = false
      @destroyed                = false
      @marked_for_destruction   = false
      @destroyed_by_association = nil
      @new_record               = true
      @txn                      = nil
      @_start_transaction_state = {}
      @transaction_state        = nil
    end

initialize_internals_callback() click to toggle source

    # File lib/active_record/core.rb, line 558
    def initialize_internals_callback
    end

sync_with_transaction_state() click to toggle source

Updates the attributes on this particular ActiveRecord object so that if it is associated with a transaction, then the state of the AR object will be updated to reflect the current state of the transaction

The @transaction_state variable stores the states of the associated transaction. This relies on the fact that a transaction can only be in one rollback or commit (otherwise a list of states would be required) Each AR object inside of a transaction carries that transaction's TransactionState.

This method checks to see if the ActiveRecord object's state reflects the TransactionState, and rolls back or commits the ActiveRecord object as appropriate.

Since ActiveRecord objects can be inside multiple transactions, this method recursively goes through the parent of the TransactionState and checks if the ActiveRecord object reflects the state of the object.

    # File lib/active_record/core.rb, line 513
    def sync_with_transaction_state
      update_attributes_from_transaction_state(@transaction_state, 0)
    end

thaw() click to toggle source

    # File lib/active_record/core.rb, line 567
    def thaw
      if frozen?
        @attributes = @attributes.dup
      end
    end

update_attributes_from_transaction_state(transaction_state, depth) click to toggle source

    # File lib/active_record/core.rb, line 517
    def update_attributes_from_transaction_state(transaction_state, depth)
      @reflects_state = [false] if depth == 0

      if transaction_state && transaction_state.finalized? && !has_transactional_callbacks?
        unless @reflects_state[depth]
          restore_transaction_record_state if transaction_state.rolledback?
          clear_transaction_record_state
          @reflects_state[depth] = true
        end

        if transaction_state.parent && !@reflects_state[depth+1]
          update_attributes_from_transaction_state(transaction_state.parent, depth+1)
        end
      end
    end