update() public method
Saves the changes to this active record into the associated database table. This method performs the following steps in order: call beforeValidate() when $runValidation is true. If beforeValidate() returns false, the rest of the steps will be skipped; call afterValidate() when $runValidation is true. If validation failed, the rest of the steps will be skipped; call beforeSave(). If beforeSave() returns false, the rest of the steps will be skipped; save the record into