Can`t think of better way to model the database - php

Question

I am trying to create a demo project where there are 3 tables: category, model, type.
There may be different categories, such as cellphone, tablets, computer, etc. For each category there are different types, such as for cellphone there could be asus, iphone, nokia, etc. Likewise, for each type there are different models: for nokia there might be nokia, lumia, nokia n97, etc. How do I create this database in symfony2 using annotations?

Answer 1

The code is not that complicated:
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity()
*/
class Category
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="string", length=255)
*/
private $name;
/**
* #ORM\OneToMany(targetEntity="Model", mappedBy="category")
*/
private $models;
}
/**
* #ORM\Entity()
*/
class Model
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(type="string", length=255)
*/
private $name;
/**
* #ManyToOne(targetEntity="Category", inversedBy="models")
* #JoinColumn(name="category_id", referencedColumnName="id")
**/
private $category;
/**
* #ORM\OneToMany(targetEntity="Type", mappedBy="model")
*/
private $types;
}
/**
* #ORM\Entity()
*/
class Type
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #ORM\Column(name="type", type="string", length=255)
*/
private $name;
/**
* #ManyToOne(targetEntity="Model", inversedBy="types")
* #JoinColumn(name="model_id", referencedColumnName="id")
**/
private $model;
}
After adding your code each one in it's file run the command:
php app/console doctrine:generate:entities
and it will generate setters and getters and constructors