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) ⇒ Object
Wrapper around
decrement
that saves the record. -
#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) ⇒ Object
Wrapper around
increment
that saves the record. -
#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.
-
#reload(options = nil) ⇒ Object
Reloads the record from the database.
-
#save ⇒ Object
Saves the model.
-
#save! ⇒ Object
Saves the model.
-
#toggle(attribute) ⇒ Object
Assigns to
attribute
the boolean opposite ofattribute?
. -
#toggle!(attribute) ⇒ Object
Wrapper around
toggle
that saves the record. -
#touch(*names) ⇒ Object
Saves the record with the updated_at/on attributes set to the current time.
-
#update(attributes) ⇒ Object
(also: #update_attributes)
Updates the attributes of the model from the passed-in hash and saves the record, all wrapped in a transaction.
-
#update!(attributes) ⇒ Object
(also: #update_attributes!)
Updates its receiver just like
update
but callssave!
instead ofsave
, so an exception is raised if the record is invalid. -
#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 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. So any change to the attributes in either instance will affect the other.
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# File 'lib/active_record/persistence.rb', line 198 def becomes(klass) became = klass.new became.instance_variable_set("@attributes", @attributes) changed_attributes = @changed_attributes if defined?(@changed_attributes) became.instance_variable_set("@changed_attributes", changed_attributes || {}) became.instance_variable_set("@new_record", new_record?) became.instance_variable_set("@destroyed", destroyed?) became.instance_variable_set("@errors", errors) 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 215 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 328 def decrement(attribute, by = 1) self[attribute] ||= 0 self[attribute] -= by self end |
#decrement!(attribute, by = 1) ⇒ Object
Wrapper around decrement
that saves the record. This method differs from its non-bang version in 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 338 def decrement!(attribute, by = 1) decrement(attribute, by).update_attribute(attribute, self[attribute]) 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.
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 155 def delete self.class.delete(id) 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 return false
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 168 def destroy raise ReadOnlyRecord, "#{self.class} is marked as readonly" if readonly? destroy_associations self.class.connection.add_transaction_record(self) destroy_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 return false
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 184 def destroy! destroy || raise(RecordNotDestroyed.new("Failed to destroy the record", self)) 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 91 def destroyed? sync_with_transaction_state @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 311 def increment(attribute, by = 1) self[attribute] ||= 0 self[attribute] += by self end |
#increment!(attribute, by = 1) ⇒ Object
Wrapper around increment
that saves the record. This method differs from its non-bang version in 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 321 def increment!(attribute, by = 1) increment(attribute, by).update_attribute(attribute, self[attribute]) 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 85 def new_record? sync_with_transaction_state @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 98 def persisted? !(new_record? || destroyed?) end |
#reload(options = nil) ⇒ Object
Reloads the record from the database.
This method finds 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 407 def reload( = nil) clear_aggregation_cache clear_association_cache self.class.connection.clear_query_cache fresh_object = if && [:lock] self.class.unscoped { self.class.lock([:lock]).find(id) } else self.class.unscoped { self.class.find(id) } end @attributes = fresh_object.instance_variable_get('@attributes') @new_record = false self end |
#save ⇒ Object
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 run validations. If any of them fail the action is cancelled and save
returns false
. However, if you supply validate: false, validations are bypassed altogether. See ActiveRecord::Validations for more information.
There’s a series of callbacks associated with save
. If any of the before_*
callbacks return false
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 119 def save(*) create_or_update rescue ActiveRecord::RecordInvalid false end |
#save! ⇒ Object
Saves the model.
If the model is new a record gets created in the database, otherwise the existing record gets updated.
With save!
validations always run. If any of them fail ActiveRecord::RecordInvalid gets raised. See ActiveRecord::Validations for more information.
There’s a series of callbacks associated with save!
. If any of the before_*
callbacks return false
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.
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# File 'lib/active_record/persistence.rb', line 141 def save!(*) create_or_update || 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
.
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# File 'lib/active_record/persistence.rb', line 346 def toggle(attribute) self[attribute] = !send("#{attribute}?") self end |
#toggle!(attribute) ⇒ Object
Wrapper around toggle
that saves the record. This method differs from its non-bang version in 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 355 def toggle!(attribute) toggle(attribute).update_attribute(attribute, self[attribute]) end |
#touch(*names) ⇒ Object
Saves the record with the updated_at/on attributes set to the current time. Please note that no validation is performed and only the after_touch
, after_commit
and after_rollback
callbacks are executed.
If attribute names are passed, they are updated along with updated_at/on attributes.
product.touch # updates updated_at/on
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 455 def touch(*names) raise ActiveRecordError, "cannot touch on a new record object" unless persisted? attributes = attributes.concat(names) unless attributes.empty? current_time = current_time_from_proper_timezone changes = {} attributes.each do |column| column = column.to_s changes[column] = write_attribute(column, current_time) end changes[self.class.locking_column] = increment_lock if locking_enabled? clear_attribute_changes(changes.keys) primary_key = self.class.primary_key self.class.unscoped.where(primary_key => self[primary_key]).update_all(changes) == 1 else true end end |
#update(attributes) ⇒ Object Also known as: update_attributes
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 247 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 Also known as: update_attributes!
Updates its receiver just like update
but calls save!
instead of save
, so an exception is raised if the record is invalid.
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# File 'lib/active_record/persistence.rb', line 260 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.
See also update_column
.
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# File 'lib/active_record/persistence.rb', line 237 def update_attribute(name, value) name = name.to_s verify_readonly_attribute(name) 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 272 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.
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 291 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 = self.class.unscoped.where(self.class.primary_key => id).update_all(attributes) attributes.each do |k, v| raw_write_attribute(k, v) end updated_count == 1 end |