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# frozen_string_literal: true
module ActiveRecord
# = Active Record \Persistence
module Persistence
extend ActiveSupport::Concern
module ClassMethods
# Creates an object (or multiple objects) and saves it to the database, if validations pass.
# The resulting object is returned whether the object was saved successfully to the database or not.
#
# The +attributes+ parameter can be either a Hash or an Array of Hashes. These Hashes describe the
# attributes on the objects that are to be created.
#
# ==== Examples
# # Create a single new object
# User.create(first_name: 'Jamie')
#
# # Create an Array of new objects
# User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }])
#
# # Create a single object and pass it into a block to set other attributes.
# User.create(first_name: 'Jamie') do |u|
# u.is_admin = false
# end
#
# # Creating an Array of new objects using a block, where the block is executed for each object:
# User.create([{ first_name: 'Jamie' }, { first_name: 'Jeremy' }]) do |u|
# u.is_admin = false
# end
def create(attributes = nil, &block)
if attributes.is_a?(Array)
attributes.collect { |attr| create(attr, &block) }
else
object = new(attributes, &block)
object.save
object
end
end
# Creates an object (or multiple objects) and saves it to the database,
# if validations pass. Raises a RecordInvalid error if validations fail,
# unlike Base#create.
#
# The +attributes+ parameter can be either a Hash or an Array of Hashes.
# These describe which attributes to be created on the object, or
# multiple objects when given an Array of Hashes.
def create!(attributes = nil, &block)
if attributes.is_a?(Array)
attributes.collect { |attr| create!(attr, &block) }
else
object = new(attributes, &block)
object.save!
object
end
end
# Given an attributes hash, +instantiate+ returns a new instance of
# the appropriate class. Accepts only keys as strings.
#
# For example, +Post.all+ may return Comments, Messages, and Emails
# by storing the record's subclass in a +type+ attribute. By calling
# +instantiate+ instead of +new+, finder methods ensure they get new
# instances of the appropriate class for each record.
#
# See <tt>ActiveRecord::Inheritance#discriminate_class_for_record</tt> to see
# how this "single-table" inheritance mapping is implemented.
def instantiate(attributes, column_types = {}, &block)
klass = discriminate_class_for_record(attributes)
attributes = klass.attributes_builder.build_from_database(attributes, column_types)
klass.allocate.init_with("attributes" => attributes, "new_record" => false, &block)
end
private
# Called by +instantiate+ to decide which class to use for a new
# record instance.
#
# See +ActiveRecord::Inheritance#discriminate_class_for_record+ for
# the single-table inheritance discriminator.
def discriminate_class_for_record(record)
self
end
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.
def new_record?
sync_with_transaction_state
@new_record
end
# Returns true if this object has been destroyed, otherwise returns false.
def destroyed?
sync_with_transaction_state
@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.
def persisted?
sync_with_transaction_state
!(@new_record || @destroyed)
end
##
# :call-seq:
# save(*args)
#
# 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
# <tt>validate: false</tt>, 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 <tt>touch: false</tt>, these
# timestamps will not be updated.
#
# There's a series of callbacks associated with #save. If any of the
# <tt>before_*</tt> 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.
def save(*args, &block)
create_or_update(*args, &block)
rescue ActiveRecord::RecordInvalid
false
end
##
# :call-seq:
# save!(*args)
#
# 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
# <tt>validate: false</tt>, 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 <tt>touch: false</tt>, these
# timestamps will not be updated.
#
# There's a series of callbacks associated with #save!. If any of
# the <tt>before_*</tt> 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.
def save!(*args, &block)
create_or_update(*args, &block) || raise(RecordNotSaved.new("Failed to save the record", self))
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?}[rdoc-ref:Core#readonly?].
#
# To enforce the object's +before_destroy+ and +after_destroy+
# callbacks or any <tt>:dependent</tt> association
# options, use <tt>#destroy</tt>.
def delete
_relation_for_itself.delete_all if persisted?
@destroyed = true
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
# <tt>before_destroy</tt> callback throws +:abort+ the action is cancelled
# and #destroy returns +false+.
# See ActiveRecord::Callbacks for further details.
def destroy
_raise_readonly_record_error if readonly?
destroy_associations
self.class.connection.add_transaction_record(self)
@_trigger_destroy_callback = if persisted?
destroy_row > 0
else
true
end
@destroyed = true
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
# <tt>before_destroy</tt> callback throws +:abort+ the action is cancelled
# and #destroy! raises ActiveRecord::RecordNotDestroyed.
# See ActiveRecord::Callbacks for further details.
def destroy!
destroy || _raise_record_not_destroyed
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 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, <tt>Client < Company</tt> to do something
# like render <tt>partial: @client.becomes(Company)</tt> 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.
# If you want to change the sti column as well, use #becomes! instead.
def becomes(klass)
became = klass.new
became.instance_variable_set("@attributes", @attributes)
became.instance_variable_set("@mutation_tracker", @mutation_tracker) if defined?(@mutation_tracker)
became.instance_variable_set("@changed_attributes", attributes_changed_by_setter)
became.instance_variable_set("@new_record", new_record?)
became.instance_variable_set("@destroyed", destroyed?)
became.errors.copy!(errors)
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.
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
# 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.
def update_attribute(name, value)
name = name.to_s
verify_readonly_attribute(name)
public_send("#{name}=", value)
if has_changes_to_save?
save(validate: false)
else
true
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.
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
alias update_attributes update
# 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.
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
alias update_attributes! update!
# Equivalent to <code>update_columns(name => value)</code>.
def update_column(name, value)
update_columns(name => value)
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.
def update_columns(attributes)
raise ActiveRecordError, "cannot update a new record" if new_record?
raise ActiveRecordError, "cannot update a destroyed record" if destroyed?
attributes.each_key do |key|
verify_readonly_attribute(key.to_s)
end
updated_count = _relation_for_itself.update_all(attributes)
attributes.each do |k, v|
write_attribute_without_type_cast(k, v)
end
updated_count == 1
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+.
def increment(attribute, by = 1)
self[attribute] ||= 0
self[attribute] += by
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+.
def increment!(attribute, by = 1, touch: nil)
increment(attribute, by)
change = public_send(attribute) - (attribute_in_database(attribute.to_s) || 0)
self.class.update_counters(id, attribute => change, touch: touch)
clear_attribute_change(attribute) # eww
self
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+.
def decrement(attribute, by = 1)
increment(attribute, -by)
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+.
def decrement!(attribute, by = 1, touch: nil)
increment!(attribute, -by, touch: touch)
end
# Assigns to +attribute+ the boolean opposite of <tt>attribute?</tt>. 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
#
def toggle(attribute)
self[attribute] = !public_send("#{attribute}?")
self
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.
def toggle!(attribute)
toggle(attribute).update_attribute(attribute, self[attribute])
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 <tt>:lock</tt> 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
#
def reload(options = nil)
self.class.connection.clear_query_cache
fresh_object =
if options && options[:lock]
self.class.unscoped { self.class.lock(options[:lock]).find(id) }
else
self.class.unscoped { self.class.find(id) }
end
@attributes = fresh_object.instance_variable_get("@attributes")
@new_record = false
self
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}[rdoc-ref:Associations::ClassMethods#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
#
def touch(*names, time: nil)
unless persisted?
raise ActiveRecordError, <<-MSG.squish
cannot touch on a new or destroyed record object. Consider using
persisted?, new_record?, or destroyed? before touching
MSG
end
time ||= current_time_from_proper_timezone
attributes = timestamp_attributes_for_update_in_model
attributes.concat(names)
unless attributes.empty?
changes = {}
attributes.each do |column|
column = column.to_s
changes[column] = write_attribute(column, time)
end
scope = _relation_for_itself
if locking_enabled?
locking_column = self.class.locking_column
scope = scope.where(locking_column => read_attribute_before_type_cast(locking_column))
changes[locking_column] = increment_lock
end
clear_attribute_changes(changes.keys)
result = scope.update_all(changes) == 1
if !result && locking_enabled?
raise ActiveRecord::StaleObjectError.new(self, "touch")
end
@_trigger_update_callback = result
result
else
true
end
end
private
# A hook to be overridden by association modules.
def destroy_associations
end
def destroy_row
relation_for_destroy.delete_all
end
def relation_for_destroy
_relation_for_itself
end
def _relation_for_itself
self.class.unscoped.where(self.class.primary_key => id)
end
def create_or_update(*args, &block)
_raise_readonly_record_error if readonly?
result = new_record? ? _create_record(&block) : _update_record(*args, &block)
result != false
end
# Updates the associated record with values matching those of the instance attributes.
# Returns the number of affected rows.
def _update_record(attribute_names = self.attribute_names)
attributes_values = arel_attributes_with_values_for_update(attribute_names)
if attributes_values.empty?
rows_affected = 0
@_trigger_update_callback = true
else
rows_affected = self.class.unscoped._update_record attributes_values, id, id_in_database
@_trigger_update_callback = rows_affected > 0
end
yield(self) if block_given?
rows_affected
end
# Creates a record with values matching those of the instance attributes
# and returns its id.
def _create_record(attribute_names = self.attribute_names)
attributes_values = arel_attributes_with_values_for_create(attribute_names)
new_id = self.class.unscoped.insert attributes_values
self.id ||= new_id if self.class.primary_key
@new_record = false
yield(self) if block_given?
id
end
def verify_readonly_attribute(name)
raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name)
end
def _raise_record_not_destroyed
@_association_destroy_exception ||= nil
raise @_association_destroy_exception || RecordNotDestroyed.new("Failed to destroy the record", self)
ensure
@_association_destroy_exception = nil
end
def belongs_to_touch_method
:touch
end
def _raise_readonly_record_error
raise ReadOnlyRecord, "#{self.class} is marked as readonly"
end
end
end