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.
# File lib/active_record/persistence.rb, line 102 def becomes(klass) became = klass.new became.instance_variable_set("@attributes", @attributes) became.instance_variable_set("@attributes_cache", @attributes_cache) became.instance_variable_set("@new_record", new_record?) became.instance_variable_set("@destroyed", destroyed?) became 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
.
# File lib/active_record/persistence.rb, line 169 def decrement(attribute, by = 1) self[attribute] ||= 0 self[attribute] -= by self end
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.
# File lib/active_record/persistence.rb, line 179 def decrement!(attribute, by = 1) decrement(attribute, by).update_attribute(attribute, self[attribute]) 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.
To enforce the object’s before_destroy
and
after_destroy
callbacks, Observer
methods, or any :dependent
association options, use
#destroy
.
# File lib/active_record/persistence.rb, line 73 def delete self.class.delete(id) 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).
# File lib/active_record/persistence.rb, line 81 def destroy destroy_associations if persisted? self.class.unscoped.where(self.class.arel_table[self.class.primary_key].eq(id)).delete_all end @destroyed = true freeze end
Returns true if this object has been destroyed, otherwise returns false.
# File lib/active_record/persistence.rb, line 11 def destroyed? @destroyed 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
.
# File lib/active_record/persistence.rb, line 152 def increment(attribute, by = 1) self[attribute] ||= 0 self[attribute] += by self end
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.
# File lib/active_record/persistence.rb, line 162 def increment!(attribute, by = 1) increment(attribute, by).update_attribute(attribute, self[attribute]) end
Returns true if this object hasn’t been saved yet – that is, a record for the object doesn’t exist in the data store yet; otherwise, returns false.
# File lib/active_record/persistence.rb, line 6 def new_record? @new_record end
Returns if the record is persisted, i.e. it’s not a new record and it was not destroyed.
# File lib/active_record/persistence.rb, line 17 def persisted? !(new_record? || destroyed?) end
Reloads the attributes of this object from the database. The optional options argument is passed to find when reloading so you may do e.g. record.reload(:lock => true) to reload the same record with an exclusive row lock.
# File lib/active_record/persistence.rb, line 204 def reload(options = nil) clear_aggregation_cache clear_association_cache @attributes.update(self.class.unscoped { self.class.find(self.id, options) }.instance_variable_get('@attributes')) @attributes_cache = {} 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 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.
# File lib/active_record/persistence.rb, line 38 def save(*) begin create_or_update rescue ActiveRecord::RecordInvalid false end end
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.
# File lib/active_record/persistence.rb, line 59 def save!(*) create_or_update || raise(RecordNotSaved) 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
.
# File lib/active_record/persistence.rb, line 187 def toggle(attribute) self[attribute] = !send("#{attribute}?") self end
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.
# File lib/active_record/persistence.rb, line 196 def toggle!(attribute) toggle(attribute).update_attribute(attribute, self[attribute]) end
Saves the record with the updated_at/on attributes set to the current time. Please note that no validation is performed and no callbacks are executed. If an attribute name is passed, that attribute is 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
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
# File lib/active_record/persistence.rb, line 232 def touch(name = nil) attributes = timestamp_attributes_for_update_in_model attributes << name if name unless attributes.empty? current_time = current_time_from_proper_timezone changes = {} attributes.each do |column| changes[column.to_s] = write_attribute(column.to_s, current_time) end @changed_attributes.except!(*changes.keys) primary_key = self.class.primary_key self.class.unscoped.update_all(changes, { primary_key => self[primary_key] }) == 1 end 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.
# File lib/active_record/persistence.rb, line 119 def update_attribute(name, value) name = name.to_s raise ActiveRecordError, "#{name} is marked as readonly" if self.class.readonly_attributes.include?(name) send("#{name}=", value) save(:validate => false) 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.
# File lib/active_record/persistence.rb, line 129 def update_attributes(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 self.attributes = attributes save end end
Updates its receiver just like update_attributes
but calls
save!
instead of save
, so an exception is raised
if the record is invalid.
# File lib/active_record/persistence.rb, line 140 def update_attributes!(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 self.attributes = attributes save! end end