Do entities always have to be based on a database in Symfony2?

Question

I have a project where DB is hidden behind web-services (many of them). In short way - direct access to DB is impossible.

I use Symfony2 and I am forcing myself to use entity every time when I have object which "store data" (for example: user, car, room) and services (accessible from container)/models when more heavier logic is involved (for example TransactionMaker, RoomBooker, CarDestroyer etc).

Entities, without any ORM descriptions, were chosen over arrays because framework provides extremely easy way to validate, build form and IDE intellisense.

Right now it works okay, but some developers claim that an entity must always reflect table in DB. Is that true?

Answer 1

Entities only map to a database table when they are configured to do so, from the book it reads:

The class - often called an "entity", meaning a basic class that holds data - is simple and helps fulfill the business requirement of needing products in your application. http://symfony.com/doc/current/book/doctrine.html#creating-an-entity-class

It is a good practice to model your data in a more formal way than using simple arrays, and this is why they exist.

Perhaps they are most commonly used to map data to the database, but that's not a requirement. They fulfill the purpose of being data-containers that model the information of your application in a way that it makes sense. (i.e. to model a USER in a USER ENTITY)

If you are not using a database to persist your entities feel free to use them to pass data around, to create forms, to use the validation service, security and so on. It could also be a good idea to create a service to allow access to the information on your web services from your Symfony app so you could have something like:

$user = $this->get('some_persistance_service_you_write')->find($id,'user');
$user->setName('new value');
$err = $this->get('validator')->validate($user);
//....
$this->get('some_persistance_service_you_write')->persist($user);

This is, of course, off topic, but it's an example of how could you use entities with no database access.