public function boot()
{
  /**
   * Inspired by @see \Illuminate\Foundation\Providers\FormRequestServiceProvider::boot()
   *
   * Note: saving event is always triggered before creating and updating events
   */
  $this->app['events']->listen('eloquent.saving: *', function (string $event_name, array $data): void {
   /** @var \App\Extensions\Illuminate\Database\Eloquent\Model $object */
   $object = $data[0];
   
   $object->validate();
  });
}

// \App\Extensions\Illuminate\Database\Eloquent\Model

use Illuminate\Database\Eloquent\Model as EloquentModel;
use Illuminate\Validation\ValidationException;

abstract class Model extends EloquentModel
{
 public function validate():void
 {
  // 1. validate type rules (type-check)
  $validator = $this->getTypeValidator();
  
  if ($validator->fails()) {
   throw new ValidationException($validator);
  }
  
  // $validator = $this->getConstraintValidator();
  // 2. validate constraint rules (sanity-check)
 }

 protected function getTypeValidator()
 {
  return $this->getValidationFactory()->make($this->attributes, static::COLUMN_TYPE_RULES);
 }
 
 protected function getValidationFactory()
 {
  return app(Factory::class);
 }
 
 protected function getConstraintValidator()
 {
  // return $this->getValidationFactory()->make($attributes, static::COLUMN_CONSTRAINT_RULES);
 } 
}

class Account extends Model
{
 public const COLUMN_TYPE_RULES = [
  'id' => 'integer|between:0,4294967295',
  'source' => 'nullable|in:schwab,orion,yodlee',
  'type' => 'required|in:bank,card,loan',
 ];
}