module ActiveRecord::Persistence

Active Record Persistence¶ ↑

Public Instance Methods

Source

# File lib/active_record/persistence.rb, line 487
def becomes(klass)
  became = klass.allocate

  became.send(:initialize) do |becoming|
    @attributes.reverse_merge!(becoming.instance_variable_get(:@attributes))
    becoming.instance_variable_set(:@attributes, @attributes)
    becoming.instance_variable_set(:@mutations_from_database, @mutations_from_database ||= nil)
    becoming.instance_variable_set(:@new_record, new_record?)
    becoming.instance_variable_set(:@destroyed, destroyed?)
    becoming.errors.copy!(errors)
  end

  became
end

Returns an instance of the specified klass with the attributes of the current record. This is mostly useful in relation to single table inheritance (STI) structures where you want a subclass to appear as the superclass. This can be used along with record identification in Action Pack to allow, say, Client < Company to do something like render client.becomes(Company) at partial: to render that instance using the companies/company partial instead of clients/client.

Note: The new instance will share a link to the same attributes as the original class. Therefore the STI column value will still be the same. Any change to the attributes on either instance will affect both instances. This includes any attribute initialization done by the new instance.

If you want to change the STI column as well, use becomes! instead.

becomes! (klass)

Source

# File lib/active_record/persistence.rb, line 508
def becomes!(klass)
  became = becomes(klass)
  sti_type = nil
  if !klass.descends_from_active_record?
    sti_type = klass.sti_name
  end
  became.public_send("#{klass.inheritance_column}=", sti_type)
  became
end

Wrapper around becomes that also changes the instance’s STI column value. This is especially useful if you want to persist the changed class in your database.

Note: The old instance’s STI column value will be changed too, as both objects share the same set of attributes.

decrement (attribute, by = 1)

Source

# File lib/active_record/persistence.rb, line 655
def decrement(attribute, by = 1)
  increment(attribute, -by)
end

Initializes attribute to zero if nil and subtracts the value passed as by (default is 1). The decrement is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returns self.

decrement! (attribute, by = 1, touch: nil)

Source

# File lib/active_record/persistence.rb, line 665
def decrement!(attribute, by = 1, touch: nil)
  increment!(attribute, -by, touch: touch)
end

Wrapper around decrement that writes the update to the database. Only attribute is updated; the record itself is not saved. This means that any other modified attributes will still be dirty. Validations and callbacks are skipped. Supports the touch option from update_counters, see that for more. Returns self.

delete ()

Source

# File lib/active_record/persistence.rb, line 439
def delete
  _delete_row if persisted?
  @destroyed = true
  @previously_new_record = false
  freeze
end

Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted). Returns the frozen instance.

The row is simply removed with an SQL DELETE statement on the record’s primary key, and no callbacks are executed.

Note that this will also delete records marked as #readonly?.

To enforce the object’s before_destroy and after_destroy callbacks or any :dependent association options, use destroy.

destroy ()

Source

# File lib/active_record/persistence.rb, line 453
def destroy
  _raise_readonly_record_error if readonly?
  destroy_associations
  @_trigger_destroy_callback ||= persisted? && destroy_row > 0
  @destroyed = true
  @previously_new_record = false
  freeze
end

Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted).

There’s a series of callbacks associated with destroy. If the before_destroy callback throws :abort the action is cancelled and destroy returns false. See ActiveRecord::Callbacks for further details.

destroy! ()

Source

# File lib/active_record/persistence.rb, line 469
def destroy!
  destroy || _raise_record_not_destroyed
end

Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted).

There’s a series of callbacks associated with destroy!. If the before_destroy callback throws :abort the action is cancelled and destroy! raises ActiveRecord::RecordNotDestroyed. See ActiveRecord::Callbacks for further details.

destroyed? ()

Source

# File lib/active_record/persistence.rb, line 355
def destroyed?
  @destroyed
end

Returns true if this object has been destroyed, otherwise returns false.

increment (attribute, by = 1)

Source

# File lib/active_record/persistence.rb, line 632
def increment(attribute, by = 1)
  self[attribute] ||= 0
  self[attribute] += by
  self
end

Initializes attribute to zero if nil and adds the value passed as by (default is 1). The increment is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returns self.

increment! (attribute, by = 1, touch: nil)

Source

# File lib/active_record/persistence.rb, line 644
def increment!(attribute, by = 1, touch: nil)
  increment(attribute, by)
  change = public_send(attribute) - (public_send(:"#{attribute}_in_database") || 0)
  self.class.update_counters(id, attribute => change, touch: touch)
  public_send(:"clear_#{attribute}_change")
  self
end

Wrapper around increment that writes the update to the database. Only attribute is updated; the record itself is not saved. This means that any other modified attributes will still be dirty. Validations and callbacks are skipped. Supports the touch option from update_counters, see that for more. Returns self.

new_record? ()

Source

# File lib/active_record/persistence.rb, line 338
def new_record?
  @new_record
end

Returns true if this object hasn’t been saved yet – that is, a record for the object doesn’t exist in the database yet; otherwise, returns false.

persisted? ()

Source

# File lib/active_record/persistence.rb, line 361
def persisted?
  !(@new_record || @destroyed)
end

Returns true if the record is persisted, i.e. it’s not a new record and it was not destroyed, otherwise returns false.

previously_new_record? ()

Source

# File lib/active_record/persistence.rb, line 345
def previously_new_record?
  @previously_new_record
end

Returns true if this object was just created – that is, prior to the last update or delete, the object didn’t exist in the database and new_record? would have returned true.

previously_persisted? ()

Source

# File lib/active_record/persistence.rb, line 350
def previously_persisted?
  !new_record? && destroyed?
end

Returns true if this object was previously persisted but now it has been deleted.

reload (options = nil)

Source

# File lib/active_record/persistence.rb, line 742
def reload(options = nil)
  self.class.connection_pool.clear_query_cache

  fresh_object = if apply_scoping?(options)
    _find_record((options || {}).merge(all_queries: true))
  else
    self.class.unscoped { _find_record(options) }
  end

  @association_cache = fresh_object.instance_variable_get(:@association_cache)
  @association_cache.each_value { |association| association.owner = self }
  @attributes = fresh_object.instance_variable_get(:@attributes)
  @new_record = false
  @previously_new_record = false
  self
end

Reloads the record from the database.

This method finds the record by its primary key (which could be assigned manually) and modifies the receiver in-place:

account = Account.new
# => #<Account id: nil, email: nil>
account.id = 1
account.reload
# Account Load (1.2ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = $1 LIMIT 1  [["id", 1]]
# => #<Account id: 1, email: 'account@example.com'>

Attributes are reloaded from the database, and caches busted, in particular the associations cache and the QueryCache.

If the record no longer exists in the database ActiveRecord::RecordNotFound is raised. Otherwise, in addition to the in-place modification the method returns self for convenience.

The optional :lock flag option allows you to lock the reloaded record:

reload(lock: true) # reload with pessimistic locking

Reloading is commonly used in test suites to test something is actually written to the database, or when some action modifies the corresponding row in the database but not the object in memory:

assert account.deposit!(25)
assert_equal 25, account.credit        # check it is updated in memory
assert_equal 25, account.reload.credit # check it is also persisted

Another common use case is optimistic locking handling:

def with_optimistic_retry
  begin
    yield
  rescue ActiveRecord::StaleObjectError
    begin
      # Reload lock_version in particular.
      reload
    rescue ActiveRecord::RecordNotFound
      # If the record is gone there is nothing to do.
    else
      retry
    end
  end
end

save(**options)

Source

# File lib/active_record/persistence.rb, line 390
def save(**options, &block)
  create_or_update(**options, &block)
rescue ActiveRecord::RecordInvalid
  false
end

Saves the model.

If the model is new, a record gets created in the database, otherwise the existing record gets updated.

By default, save always runs validations. If any of them fail the action is cancelled and save returns false, and the record won’t be saved. However, if you supply validate: false, validations are bypassed altogether. See ActiveRecord::Validations for more information.

By default, save also sets the updated_at/updated_on attributes to the current time. However, if you supply touch: false, these timestamps will not be updated.

There’s a series of callbacks associated with save. If any of the before_* callbacks throws :abort the action is cancelled and save returns false. See ActiveRecord::Callbacks for further details.

Attributes marked as readonly are silently ignored if the record is being updated.

save!(**options)

Source

# File lib/active_record/persistence.rb, line 423
def save!(**options, &block)
  create_or_update(**options, &block) || raise(RecordNotSaved.new("Failed to save the record", self))
end

Saves the model.

If the model is new, a record gets created in the database, otherwise the existing record gets updated.

By default, save! always runs validations. If any of them fail ActiveRecord::RecordInvalid gets raised, and the record won’t be saved. However, if you supply validate: false, validations are bypassed altogether. See ActiveRecord::Validations for more information.

By default, save! also sets the updated_at/updated_on attributes to the current time. However, if you supply touch: false, these timestamps will not be updated.

There’s a series of callbacks associated with save!. If any of the before_* callbacks throws :abort the action is cancelled and save! raises ActiveRecord::RecordNotSaved. See ActiveRecord::Callbacks for further details.

Attributes marked as readonly are silently ignored if the record is being updated.

Unless an error is raised, returns true.

toggle (attribute)

Source

# File lib/active_record/persistence.rb, line 681
def toggle(attribute)
  self[attribute] = !public_send("#{attribute}?")
  self
end

Assigns to attribute the boolean opposite of attribute?. So if the predicate returns true the attribute will become false. This method toggles directly the underlying value without calling any setter. Returns self.

Example:

user = User.first
user.banned? # => false
user.toggle(:banned)
user.banned? # => true

toggle! (attribute)

Source

# File lib/active_record/persistence.rb, line 690
def toggle!(attribute)
  toggle(attribute).update_attribute(attribute, self[attribute])
end

Wrapper around toggle that saves the record. This method differs from its non-bang version in the sense that it passes through the attribute setter. Saving is not subjected to validation checks. Returns true if the record could be saved.

touch (*names, time: nil)

Source

# File lib/active_record/persistence.rb, line 793
def touch(*names, time: nil)
  _raise_record_not_touched_error unless persisted?
  _raise_readonly_record_error if readonly?

  attribute_names = timestamp_attributes_for_update_in_model
  attribute_names = (attribute_names | names).map! do |name|
    name = name.to_s
    name = self.class.attribute_aliases[name] || name
    verify_readonly_attribute(name)
    name
  end

  unless attribute_names.empty?
    affected_rows = _touch_row(attribute_names, time)
    @_trigger_update_callback = affected_rows == 1
  else
    true
  end
end

Saves the record with the updated_at/on attributes set to the current time or the time specified. Please note that no validation is performed and only the after_touch, after_commit and after_rollback callbacks are executed.

This method can be passed attribute names and an optional time argument. If attribute names are passed, they are updated along with updated_at/on attributes. If no time argument is passed, the current time is used as default.

product.touch                         # updates updated_at/on with current time
product.touch(time: Time.new(2015, 2, 16, 0, 0, 0)) # updates updated_at/on with specified time
product.touch(:designed_at)           # updates the designed_at attribute and updated_at/on
product.touch(:started_at, :ended_at) # updates started_at, ended_at and updated_at/on attributes

If used along with belongs_to then touch will invoke touch method on associated object.

class Brake < ActiveRecord::Base
  belongs_to :car, touch: true
end

class Car < ActiveRecord::Base
  belongs_to :corporation, touch: true
end

# triggers @brake.car.touch and @brake.car.corporation.touch
@brake.touch

Note that touch must be used on a persisted object, or else an ActiveRecordError will be thrown. For example:

ball = Ball.new
ball.touch(:updated_at)   # => raises ActiveRecordError

update (attributes)

Source

# File lib/active_record/persistence.rb, line 563
def update(attributes)
  # The following transaction covers any possible database side-effects of the
  # attributes assignment. For example, setting the IDs of a child collection.
  with_transaction_returning_status do
    assign_attributes(attributes)
    save
  end
end

Updates the attributes of the model from the passed-in hash and saves the record, all wrapped in a transaction. If the object is invalid, the saving will fail and false will be returned.

update! (attributes)

Source

# File lib/active_record/persistence.rb, line 574
def update!(attributes)
  # The following transaction covers any possible database side-effects of the
  # attributes assignment. For example, setting the IDs of a child collection.
  with_transaction_returning_status do
    assign_attributes(attributes)
    save!
  end
end

Updates its receiver just like update but calls save! instead of save, so an exception is raised if the record is invalid and saving will fail.

update_attribute (name, value)

Source

# File lib/active_record/persistence.rb, line 530
def update_attribute(name, value)
  name = name.to_s
  verify_readonly_attribute(name)
  public_send("#{name}=", value)

  save(validate: false)
end

Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records. Also note that

Validation is skipped.
Callbacks are invoked.
updated_at/updated_on column is updated if that column is available.
Updates all the attributes that are dirty in this object.

This method raises an ActiveRecord::ActiveRecordError if the attribute is marked as readonly.

Also see update_column.

update_attribute! (name, value)

Source

# File lib/active_record/persistence.rb, line 552
def update_attribute!(name, value)
  name = name.to_s
  verify_readonly_attribute(name)
  public_send("#{name}=", value)

  save!(validate: false)
end

Updates a single attribute and saves the record. This is especially useful for boolean flags on existing records. Also note that

Validation is skipped.
Callbacks are invoked.
updated_at/updated_on column is updated if that column is available.
Updates all the attributes that are dirty in this object.

This method raises an ActiveRecord::ActiveRecordError if the attribute is marked as readonly.

If any of the before_* callbacks throws :abort the action is cancelled and update_attribute! raises ActiveRecord::RecordNotSaved. See ActiveRecord::Callbacks for further details.

update_column (name, value)

Source

# File lib/active_record/persistence.rb, line 584
def update_column(name, value)
  update_columns(name => value)
end

Equivalent to update_columns(name => value).

update_columns (attributes)

Source

# File lib/active_record/persistence.rb, line 604
def update_columns(attributes)
  raise ActiveRecordError, "cannot update a new record" if new_record?
  raise ActiveRecordError, "cannot update a destroyed record" if destroyed?
  _raise_readonly_record_error if readonly?

  attributes = attributes.transform_keys do |key|
    name = key.to_s
    name = self.class.attribute_aliases[name] || name
    verify_readonly_attribute(name) || name
  end

  update_constraints = _query_constraints_hash
  attributes = attributes.each_with_object({}) do |(k, v), h|
    h[k] = @attributes.write_cast_value(k, v)
    clear_attribute_change(k)
  end

  affected_rows = self.class._update_record(
    attributes,
    update_constraints
  )

  affected_rows == 1
end

Updates the attributes directly in the database issuing an UPDATE SQL statement and sets them in the receiver:

user.update_columns(last_request_at: Time.current)

This is the fastest way to update attributes because it goes straight to the database, but take into account that in consequence the regular update procedures are totally bypassed. In particular:

Validations are skipped.
Callbacks are skipped.
updated_at/updated_on are not updated.
However, attributes are serialized with the same rules as ActiveRecord::Relation#update_all

This method raises an ActiveRecord::ActiveRecordError when called on new objects, or when at least one of the attributes is marked as readonly.

Private Instance Methods

_create_record (attribute_names = self.attribute_names) { |self| ... }

Source

# File lib/active_record/persistence.rb, line 920
def _create_record(attribute_names = self.attribute_names)
  attribute_names = attributes_for_create(attribute_names)

  self.class.with_connection do |connection|
    returning_columns = self.class._returning_columns_for_insert(connection)

    returning_values = self.class._insert_record(
      connection,
      attributes_with_values(attribute_names),
      returning_columns
    )

    returning_columns.zip(returning_values).each do |column, value|
      _write_attribute(column, type_for_attribute(column).deserialize(value)) if !_read_attribute(column)
    end if returning_values
  end

  @new_record = false
  @previously_new_record = true

  yield(self) if block_given?

  id
end

Creates a record with values matching those of the instance attributes and returns its id.

_delete_row ()

Source

# File lib/active_record/persistence.rb, line 870
def _delete_row
  self.class._delete_record(_query_constraints_hash)
end

_find_record (options)

Source

# File lib/active_record/persistence.rb, line 826
def _find_record(options)
  all_queries = options ? options[:all_queries] : nil
  base = self.class.all(all_queries: all_queries).preload(strict_loaded_associations)

  if options && options[:lock]
    base.lock(options[:lock]).find_by!(_in_memory_query_constraints_hash)
  else
    base.find_by!(_in_memory_query_constraints_hash)
  end
end

_in_memory_query_constraints_hash ()

Source

# File lib/active_record/persistence.rb, line 837
def _in_memory_query_constraints_hash
  if self.class.query_constraints_list.nil?
    { @primary_key => id }
  else
    self.class.query_constraints_list.index_with do |column_name|
      attribute(column_name)
    end
  end
end

_query_constraints_hash ()

Source

# File lib/active_record/persistence.rb, line 852
def _query_constraints_hash
  if self.class.query_constraints_list.nil?
    { @primary_key => id_in_database }
  else
    self.class.query_constraints_list.index_with do |column_name|
      attribute_in_database(column_name)
    end
  end
end

_raise_readonly_record_error ()

Source

# File lib/active_record/persistence.rb, line 957
def _raise_readonly_record_error
  raise ReadOnlyRecord, "#{self.class} is marked as readonly"
end

_raise_record_not_destroyed ()

Source

# File lib/active_record/persistence.rb, line 949
def _raise_record_not_destroyed
  @_association_destroy_exception ||= nil
  key = self.class.primary_key
  raise @_association_destroy_exception || RecordNotDestroyed.new("Failed to destroy #{self.class} with #{key}=#{id}", self)
ensure
  @_association_destroy_exception = nil
end

_raise_record_not_touched_error ()

Source

# File lib/active_record/persistence.rb, line 961
      def _raise_record_not_touched_error
        raise ActiveRecordError, <<~MSG.squish
          Cannot touch on a new or destroyed record object. Consider using
          persisted?, new_record?, or destroyed? before touching.
        MSG
      end

_touch_row (attribute_names, time)

Source

# File lib/active_record/persistence.rb, line 874
def _touch_row(attribute_names, time)
  time ||= current_time_from_proper_timezone

  attribute_names.each do |attr_name|
    _write_attribute(attr_name, time)
  end

  _update_row(attribute_names, "touch")
end

_update_record (attribute_names = self.attribute_names) { |self| ... }

Source

# File lib/active_record/persistence.rb, line 900
def _update_record(attribute_names = self.attribute_names)
  attribute_names = attributes_for_update(attribute_names)

  if attribute_names.empty?
    affected_rows = 0
    @_trigger_update_callback = true
  else
    affected_rows = _update_row(attribute_names)
    @_trigger_update_callback = affected_rows == 1
  end

  @previously_new_record = false

  yield(self) if block_given?

  affected_rows
end

Updates the associated record with values matching those of the instance attributes. Returns the number of affected rows.

_update_row (attribute_names, attempted_action = "update")

Source

# File lib/active_record/persistence.rb, line 884
def _update_row(attribute_names, attempted_action = "update")
  self.class._update_record(
    attributes_with_values(attribute_names),
    _query_constraints_hash
  )
end

apply_scoping? (options)

Source

# File lib/active_record/persistence.rb, line 847
def apply_scoping?(options)
  !(options && options[:unscoped]) &&
    (self.class.default_scopes?(all_queries: true) || self.class.global_current_scope)
end

create_or_update (**, &block)

Source

# File lib/active_record/persistence.rb, line 891
def create_or_update(**, &block)
  _raise_readonly_record_error if readonly?
  return false if destroyed?
  result = new_record? ? _create_record(&block) : _update_record(&block)
  result != false
end

destroy_associations ()

Source

# File lib/active_record/persistence.rb, line 863
def destroy_associations
end

A hook to be overridden by association modules.

destroy_row ()

Source

# File lib/active_record/persistence.rb, line 866
def destroy_row
  _delete_row
end

init_internals ()

Source

# File lib/active_record/persistence.rb, line 814
def init_internals
  super
  @_trigger_destroy_callback = @_trigger_update_callback = nil
  @previously_new_record = false
end

Calls superclass method

strict_loaded_associations ()

Source

# File lib/active_record/persistence.rb, line 820
def strict_loaded_associations
  @association_cache.find_all do |_, assoc|
    assoc.owner.strict_loading? && !assoc.owner.strict_loading_n_plus_one_only?
  end.map(&:first)
end

verify_readonly_attribute (name)

Source

# File lib/active_record/persistence.rb, line 945
def verify_readonly_attribute(name)
  raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attribute?(name)
end