Getting associated entries in Doctrine 2 - php

Question

I've decided that it would be a good asset to get familiar with an ORM and went for Doctrine 2 as the ORM of choice.
I'm working on a test project to learn the basics of Doctrine. Although most people usually go with a blog, I've decided to make a basic app in which you can save and track orders. My database schema would be as follows:
User
id
name
Product
id
name
price
Sales_order
id
user_id
product_id
quantity
unit_price
Hence, my Order model looks like:
/**
* #Entity
* #Table(name="sales_order")
*/
class Order {
/**
* #Id
* #Column(type="integer", nullable=false)
* #GeneratedValue(strategy="AUTO")
*/
private $Id;
/**
* #OneToOne(targetEntity="User", inversedBy="user")
*/
private $user;
/**
* #OneToOne(targetEntity="Product", inversedBy="product")
*/
private $product;
/**
* #Column(type="integer", nullable=false)
*/
private $quantity;
}
Now, the question is, is there a simple way of accessing all the orders from the user model? Should I write DQL (doctrine query language) for these kind of basic stuff or is there a way to easily get associated entities? I mean, there wouldn't be any point to this otherwise, right? Also, am I doing these associations correctly? I'm really confused in this very basic model... Detailed help is really appreciated. Thank you.

Answer 1

Firstly, don't worry too much about the database design. You should design your entities and use the SchemaTool.
Now, the question is, is there a simple way of accessing all the orders from the user model?
Do you mean access all of the orders from the user model, or access all the orders associated to a user?
If you meant the former, well you are doing things wrong (see below). If you meant the later, you should setup a bi-directional relationship between orders and users. (BTW, it would be OneToMany not OneToOne as one user would likely have many orders).
I'm really confused in this very basic model...
I think what you having trouble with - along with many PHP programmers - is the fundamental understandings of the DataMapper pattern and ultimately Domain Driven Design as well. Remember, you are dealing with persistable objects, not database tables.
I cannot provide detailed information here because I'd be writing a book, hence this I would recommend you get a book on Domain Driven Design to help kick start with the principles. There are a few good online resources available, like a series of blog posts by Federico Cargnelutti, however they aren't specific to Doctrine 2.