Returns an instance of the specifiedklass 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 renderpartial: @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. This includes any attribute initialization done by the new instance.

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 487defbecomes(klass)became =klass.allocatebecame.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(:@previously_new_record,previously_new_record?)becoming.instance_variable_set(:@destroyed,destroyed?)becoming.errors.copy!(errors)endbecameend

Wrapper aroundbecomes 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.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 509defbecomes!(klass)became =becomes(klass)sti_type =nilif!klass.descends_from_active_record?sti_type =klass.sti_nameendbecame.public_send("#{klass.inheritance_column}=",sti_type)becameend

Initializesattribute to zero ifnil and subtracts the value passed asby (default is 1). The decrement is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returnsself.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 686defdecrement(attribute,by =1)increment(attribute,-by)end

Wrapper arounddecrement that writes the update to the database. Onlyattribute 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 thetouch option fromupdate_counters, see that for more. Returnsself.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 696defdecrement!(attribute,by =1,touch:nil)increment!(attribute,-by,touch:touch)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 SQLDELETE 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’sbefore_destroy andafter_destroy callbacks or any:dependent association options, usedestroy.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 439defdelete_delete_rowifpersisted?@destroyed =true@previously_new_record =falsefreezeend

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 withdestroy. If thebefore_destroy callback throws:abort the action is cancelled anddestroy returnsfalse. SeeActiveRecord::Callbacks for further details.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 453defdestroy_raise_readonly_record_errorifreadonly?destroy_associations@_trigger_destroy_callback||=persisted?&&destroy_row>0@destroyed =true@previously_new_record =falsefreezeend

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 withdestroy!. If thebefore_destroy callback throws:abort the action is cancelled anddestroy! raisesActiveRecord::RecordNotDestroyed. SeeActiveRecord::Callbacks for further details.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 469defdestroy!destroy||_raise_record_not_destroyedend

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 355defdestroyed?@destroyedend

Initializesattribute to zero ifnil and adds the value passed asby (default is 1). The increment is performed directly on the underlying attribute, no setter is invoked. Only makes sense for number-based attributes. Returnsself.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 656defincrement(attribute,by =1)self[attribute]||=0self[attribute]+=byselfend

Wrapper aroundincrement that writes the update to the database. Onlyattribute 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 thetouch option fromupdate_counters, see that for more.

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

Returnsself.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 672defincrement!(attribute,by =1,touch:nil)raiseActiveRecordError,"cannot update a new record"ifnew_record?raiseActiveRecordError,"cannot update a destroyed record"ifdestroyed?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")selfend

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.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 338defnew_record?@new_recordend

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 361defpersisted?!(@new_record||@destroyed)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.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 345defpreviously_new_record?@previously_new_recordend

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 350defpreviously_persisted?!new_record?&&destroyed?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 =1account.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 theQueryCache.

If the record no longer exists in the databaseActiveRecord::RecordNotFound is raised. Otherwise, in addition to the in-place modification the method returnsself 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:

assertaccount.deposit!(25)assert_equal25,account.credit# check it is updated in memoryassert_equal25,account.reload.credit# check it is also persisted

Another common use case is optimistic locking handling:

defwith_optimistic_retrybeginyieldrescueActiveRecord::StaleObjectErrorbegin# Reload lock_version in particular.reloadrescueActiveRecord::RecordNotFound# If the record is gone there is nothing to do.elseretryendendend

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 773defreload(options =nil)self.class.connection_pool.clear_query_cachefresh_object =ifapply_scoping?(options)_find_record((options|| {}).merge(all_queries:true))elseself.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 =falseselfend

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 andsave returnsfalse, and the record won’t be saved. However, if you supplyvalidate: false, validations are bypassed altogether. SeeActiveRecord::Validations for more information.

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

There’s a series of callbacks associated withsave. If any of thebefore_* callbacks throws:abort the action is cancelled andsave returnsfalse. SeeActiveRecord::Callbacks for further details.

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 390defsave(**options,&block)create_or_update(**options,&block)rescueActiveRecord::RecordInvalidfalseend

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 failActiveRecord::RecordInvalid gets raised, and the record won’t be saved. However, if you supplyvalidate: false, validations are bypassed altogether. SeeActiveRecord::Validations for more information.

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

There’s a series of callbacks associated withsave!. If any of thebefore_* callbacks throws:abort the action is cancelled andsave! raisesActiveRecord::RecordNotSaved. SeeActiveRecord::Callbacks for further details.

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

Unless an error is raised, returns true.

Source:show |on GitHub

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

Assigns toattribute the boolean opposite ofattribute?. So if the predicate returnstrue the attribute will becomefalse. This method toggles directly the underlying value without calling any setter. Returnsself.

Example:

user =User.firstuser.banned?# => falseuser.toggle(:banned)user.banned?# => true

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 712deftoggle(attribute)self[attribute] =!public_send("#{attribute}?")selfend

Wrapper aroundtoggle 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. Returnstrue if the record could be saved.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 721deftoggle!(attribute)toggle(attribute).update_attribute(attribute,self[attribute])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 theafter_touch,after_commit andafter_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 timeproduct.touch(time:Time.new(2015,2,16,0,0,0))# updates updated_at/on with specified timeproduct.touch(:designed_at)# updates the designed_at attribute and updated_at/onproduct.touch(:started_at,:ended_at)# updates started_at, ended_at and updated_at/on attributes

If used along withbelongs_to thentouch will invoketouch method on associated object.

classBrake<ActiveRecord::Basebelongs_to:car,touch:trueendclassCar<ActiveRecord::Basebelongs_to:corporation,touch:trueend# triggers @brake.car.touch and @brake.car.corporation.touch@brake.touch

Note thattouch must be used on a persisted object, or else anActiveRecordError will be thrown. For example:

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

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 824deftouch(*names,time:nil)_raise_record_not_touched_errorunlesspersisted?_raise_readonly_record_errorifreadonly?attribute_names =timestamp_attributes_for_update_in_modelattribute_names = (attribute_names|names).map!do|name|name =name.to_sname =self.class.attribute_aliases[name]||nameverify_readonly_attribute(name)nameendunlessattribute_names.empty?affected_rows =_touch_row(attribute_names,time)@_trigger_update_callback =affected_rows==1elsetrueendend

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.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 564defupdate(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_statusdoassign_attributes(attributes)saveendend

Updates its receiver just likeupdate but callssave! instead ofsave, so an exception is raised if the record is invalid and saving will fail.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 575defupdate!(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_statusdoassign_attributes(attributes)save!endend

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 anActiveRecord::ActiveRecordError if the attribute is marked as readonly.

Also seeupdate_column.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 531defupdate_attribute(name,value)name =name.to_sverify_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 anActiveRecord::ActiveRecordError if the attribute is marked as readonly.

If any of thebefore_* callbacks throws:abort the action is cancelled andupdate_attribute! raisesActiveRecord::RecordNotSaved. SeeActiveRecord::Callbacks for further details.

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 553defupdate_attribute!(name,value)name =name.to_sverify_readonly_attribute(name)public_send("#{name}=",value)save!(validate:false)end

Equivalent toupdate_columns(name => value).

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 585defupdate_column(name,value,touch:nil)update_columns(name=>value,touch:touch)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 updated if thetouch option is set totrue.

• However, attributes are serialized with the same rules asActiveRecord::Relation#update_all

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

Parameters¶↑

• :touch option - Touch the timestamp columns when updating.

• If attribute names are passed, they are updated along withupdated_at/updated_on attributes.

Examples¶↑

# Update a single attribute.user.update_columns(last_request_at:Time.current)# Update with touch option.user.update_columns(last_request_at:Time.current,touch:true)

Source:show |on GitHub

# File activerecord/lib/active_record/persistence.rb, line 619defupdate_columns(attributes)raiseActiveRecordError,"cannot update a new record"ifnew_record?raiseActiveRecordError,"cannot update a destroyed record"ifdestroyed?_raise_readonly_record_errorifreadonly?attributes =attributes.transform_keysdo|key|name =key.to_sname =self.class.attribute_aliases[name]||nameverify_readonly_attribute(name)||nameendtouch =attributes.delete("touch")iftouchnames =touchiftouch!=truenames =Array.wrap(names)options =names.extract_options!touch_updates =self.class.touch_attributes_with_time(*names,**options)attributes.with_defaults!(touch_updates)unlesstouch_updates.empty?endupdate_constraints =_query_constraints_hashattributes =attributes.each_with_object({})do|(k,v),h|h[k] =@attributes.write_cast_value(k,v)clear_attribute_change(k)endaffected_rows =self.class._update_record(attributes,update_constraints  )affected_rows==1end