module ActiveRecord::Core

Public Class Methods

connection_handler() click to toggle source
# File lib/active_record/core.rb, line 82
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 86
def self.connection_handler=(handler)
  ActiveRecord::RuntimeRegistry.connection_handler = handler
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 170
def initialize(attributes = nil, options = {})
  defaults = self.class.column_defaults.dup
  defaults.each { |k, v| defaults[k] = v.dup if v.duplicable? }

  @attributes   = self.class.initialize_attributes(defaults)
  @column_types_override = nil
  @column_types = self.class.column_types

  init_internals
  init_changed_attributes
  ensure_proper_type
  populate_with_current_scope_attributes

  # +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_callbacks :initialize unless _initialize_callbacks.empty?
end

Public Instance Methods

<=>(other_object) click to toggle source

Allows sort on objects

# File lib/active_record/core.rb, line 318
def <=>(other_object)
  if other_object.is_a?(self.class)
    self.to_key <=> other_object.to_key
  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 290
def ==(comparison_object)
  super ||
    comparison_object.instance_of?(self.class) &&
    id.present? &&
    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 233
    
connection() click to toggle source

Returns the connection currently associated with the class. This can also be used to “borrow” the connection to do database work that isn't easily done without going straight to SQL.

# File lib/active_record/core.rb, line 338
def connection
  ActiveSupport::Deprecation.warn("#connection is deprecated in favour of accessing it via the class")
  self.class.connection
end
connection_handler() click to toggle source
# File lib/active_record/core.rb, line 343
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 242
    
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 277
def encode_with(coder)
  coder['attributes'] = attributes
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 307
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 313
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) ]
# File lib/active_record/core.rb, line 300
def hash
  id.hash
end
init_with(coder) click to toggle source

Initialize an empty model object from coder. coder must contain the attributes necessary for initializing an empty model object. For example:

class Post < ActiveRecord::Base
end

post = Post.allocate
post.init_with('attributes' => { 'title' => 'hello world' })
post.title # => 'hello world'
# File lib/active_record/core.rb, line 201
def init_with(coder)
  @attributes   = self.class.initialize_attributes(coder['attributes'])
  @column_types_override = coder['column_types']
  @column_types = self.class.column_types

  init_internals

  @new_record = false

  run_callbacks :find
  run_callbacks :initialize

  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 348
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
readonly!() click to toggle source

Marks this record as read only.

# File lib/active_record/core.rb, line 331
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 326
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 364
def slice(*methods)
  Hash[methods.map { |method| [method, public_send(method)] }].with_indifferent_access
end

Private Instance Methods

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 459
def init_attributes(attributes, options)
  assign_attributes(attributes)
end
init_changed_attributes() click to toggle source
# File lib/active_record/core.rb, line 448
def init_changed_attributes
  # Intentionally avoid using #column_defaults since overridden defaults (as is done in
  # optimistic locking) won't get written unless they get marked as changed
  self.class.columns.each do |c|
    attr, orig_value = c.name, c.default
    @changed_attributes[attr] = orig_value if _field_changed?(attr, orig_value, @attributes[attr])
  end
end
init_internals() click to toggle source
# File lib/active_record/core.rb, line 428
def init_internals
  pk = self.class.primary_key
  @attributes[pk] = nil unless @attributes.key?(pk)

  @aggregation_cache        = {}
  @association_cache        = {}
  @attributes_cache         = {}
  @previously_changed       = {}
  @changed_attributes       = {}
  @readonly                 = false
  @destroyed                = false
  @marked_for_destruction   = false
  @destroyed_by_association = nil
  @new_record               = true
  @txn                      = nil
  @_start_transaction_state = {}
  @transaction_state        = nil
  @reflects_state           = [false]
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 395
def sync_with_transaction_state
  update_attributes_from_transaction_state(@transaction_state, 0)
end
update_attributes_from_transaction_state(transaction_state, depth) click to toggle source
# File lib/active_record/core.rb, line 399
def update_attributes_from_transaction_state(transaction_state, depth)
  if transaction_state && !has_transactional_callbacks?
    unless @reflects_state[depth]
      if transaction_state.committed?
        committed!
      elsif transaction_state.rolledback?
        rolledback!
      end
      @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