Module: ActiveRecord::Persistence
Overview
Active Record Persistence
Defined Under Namespace
Modules: ClassMethods
Instance Method Summary collapse
-
#becomes(klass) ⇒ Object
Returns an instance of the specified
klass
with the attributes of the current record. -
#becomes!(klass) ⇒ Object
Wrapper around #becomes that also changes the instance’s STI column value.
-
#decrement(attribute, by = 1) ⇒ Object
Initializes
attribute
to zero ifnil
and subtracts the value passed asby
(default is 1). -
#decrement!(attribute, by = 1, touch: nil) ⇒ Object
Wrapper around #decrement that writes the update to the database.
-
#delete ⇒ Object
Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted).
-
#destroy ⇒ Object
Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted).
-
#destroy! ⇒ Object
Deletes the record in the database and freezes this instance to reflect that no changes should be made (since they can’t be persisted).
-
#destroyed? ⇒ Boolean
Returns true if this object has been destroyed, otherwise returns false.
-
#increment(attribute, by = 1) ⇒ Object
Initializes
attribute
to zero ifnil
and adds the value passed asby
(default is 1). -
#increment!(attribute, by = 1, touch: nil) ⇒ Object
Wrapper around #increment that writes the update to the database.
-
#new_record? ⇒ Boolean
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? ⇒ Boolean
Returns true if the record is persisted, i.e.
-
#previously_new_record? ⇒ Boolean
Returns true if this object was just created – that is, prior to the last save, the object didn’t exist in the database and new_record? would have returned true.
-
#previously_persisted? ⇒ Boolean
Returns true if this object was previously persisted but now it has been deleted.
-
#reload(options = nil) ⇒ Object
Reloads the record from the database.
-
#save(**options, &block) ⇒ Object
:call-seq: save(**options).
-
#save!(**options, &block) ⇒ Object
:call-seq: save!(**options).
-
#toggle(attribute) ⇒ Object
Assigns to
attribute
the boolean opposite ofattribute?
. -
#toggle!(attribute) ⇒ Object
Wrapper around #toggle that saves the record.
-
#touch(*names, time: nil) ⇒ Object
Saves the record with the updated_at/on attributes set to the current time or the time specified.
-
#update(attributes) ⇒ Object
Updates the attributes of the model from the passed-in hash and saves the record, all wrapped in a transaction.
-
#update!(attributes) ⇒ Object
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) ⇒ Object
Updates a single attribute and saves the record.
-
#update_column(name, value) ⇒ Object
Equivalent to
update_columns(name => value)
. -
#update_columns(attributes) ⇒ Object
Updates the attributes directly in the database issuing an UPDATE SQL statement and sets them in the receiver:.
Instance Method Details
#becomes(klass) ⇒ Object
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 partial: @client.becomes(Company)
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.
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# File 'lib/active_record/persistence.rb', line 712 def becomes(klass) became = klass.allocate became.send(:initialize) do |becoming| 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 |
#becomes!(klass) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 732 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 |
#decrement(attribute, by = 1) ⇒ Object
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
.
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# File 'lib/active_record/persistence.rb', line 856 def decrement(attribute, by = 1) increment(attribute, -by) end |
#decrement!(attribute, by = 1, touch: nil) ⇒ Object
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
.
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# File 'lib/active_record/persistence.rb', line 866 def decrement!(attribute, by = 1, touch: nil) increment!(attribute, -by, touch: touch) end |
#delete ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 664 def delete _delete_row if persisted? @destroyed = true freeze end |
#destroy ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 677 def destroy _raise_readonly_record_error if readonly? destroy_associations @_trigger_destroy_callback = if persisted? destroy_row > 0 else true end @destroyed = true freeze end |
#destroy! ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 696 def destroy! destroy || _raise_record_not_destroyed end |
#destroyed? ⇒ Boolean
Returns true if this object has been destroyed, otherwise returns false.
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# File 'lib/active_record/persistence.rb', line 580 def destroyed? @destroyed end |
#increment(attribute, by = 1) ⇒ Object
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
.
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# File 'lib/active_record/persistence.rb', line 833 def increment(attribute, by = 1) self[attribute] ||= 0 self[attribute] += by self end |
#increment!(attribute, by = 1, touch: nil) ⇒ Object
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
.
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# File 'lib/active_record/persistence.rb', line 845 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 |
#new_record? ⇒ Boolean
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.
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# File 'lib/active_record/persistence.rb', line 563 def new_record? @new_record end |
#persisted? ⇒ Boolean
Returns true if the record is persisted, i.e. it’s not a new record and it was not destroyed, otherwise returns false.
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# File 'lib/active_record/persistence.rb', line 586 def persisted? !(@new_record || @destroyed) end |
#previously_new_record? ⇒ Boolean
Returns true if this object was just created – that is, prior to the last save, the object didn’t exist in the database and new_record? would have returned true.
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# File 'lib/active_record/persistence.rb', line 570 def previously_new_record? @previously_new_record end |
#previously_persisted? ⇒ Boolean
Returns true if this object was previously persisted but now it has been deleted.
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# File 'lib/active_record/persistence.rb', line 575 def previously_persisted? !new_record? && destroyed? end |
#reload(options = nil) ⇒ Object
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: '[email protected]'>
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
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# File 'lib/active_record/persistence.rb', line 943 def reload( = nil) self.class.connection.clear_query_cache fresh_object = if apply_scoping?() _find_record() else self.class.unscoped { _find_record() } end @association_cache = fresh_object.instance_variable_get(:@association_cache) @attributes = fresh_object.instance_variable_get(:@attributes) @new_record = false @previously_new_record = false self end |
#save(**options, &block) ⇒ Object
:call-seq:
save(**)
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.
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# File 'lib/active_record/persistence.rb', line 615 def save(**, &block) create_or_update(**, &block) rescue ActiveRecord::RecordInvalid false end |
#save!(**options, &block) ⇒ Object
:call-seq:
save!(**)
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.
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# File 'lib/active_record/persistence.rb', line 648 def save!(**, &block) create_or_update(**, &block) || raise(RecordNotSaved.new("Failed to save the record", self)) end |
#toggle(attribute) ⇒ Object
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
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# File 'lib/active_record/persistence.rb', line 882 def toggle(attribute) self[attribute] = !public_send("#{attribute}?") self end |
#toggle!(attribute) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 891 def toggle!(attribute) toggle(attribute).update_attribute(attribute, self[attribute]) end |
#touch(*names, time: nil) ⇒ Object
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
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# File 'lib/active_record/persistence.rb', line 993 def touch(*names, time: nil) _raise_record_not_touched_error unless persisted? attribute_names = attribute_names |= names.map! do |name| name = name.to_s self.class.attribute_aliases[name] || name end unless names.empty? unless attribute_names.empty? affected_rows = _touch_row(attribute_names, time) @_trigger_update_callback = affected_rows == 1 else true end end |
#update(attributes) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 765 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 |
#update!(attributes) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 776 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 |
#update_attribute(name, value) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 754 def update_attribute(name, value) name = name.to_s verify_readonly_attribute(name) public_send("#{name}=", value) save(validate: false) end |
#update_column(name, value) ⇒ Object
Equivalent to update_columns(name => value)
.
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# File 'lib/active_record/persistence.rb', line 786 def update_column(name, value) update_columns(name => value) end |
#update_columns(attributes) ⇒ Object
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.
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# File 'lib/active_record/persistence.rb', line 806 def update_columns(attributes) raise ActiveRecordError, "cannot update a new record" if new_record? raise ActiveRecordError, "cannot update a destroyed record" if destroyed? 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 = _primary_key_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 |