How to fetch data from another entity using Doctrine 2

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How to fetch data from another entity using Doctrine 2

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I have two entities a Product (id, category_id, name) and another Category (id, name), in the product entity want to bring the name of the category by the category_id of the product table. Is there a way to do this with annotations?

php orm doctrine

asked by anonymous 16.12.2014 / 19:52

1 answer

Java Serial Communication Clear Context using persistence CoreData

score 0 · Accepted Answer

After reading the question I saw that it is a Many-To-One association. Come on then: you need to create two classes - Produto and Categoria - and map relationships using annotations. The relationship can be made in a number of different ways, either unidirectional (relationship information stays in only one entity) or bidirectional (relationship information stays in both entities). Personally I prefer the latter, which is what I will use to explain your case.

Class Produto :

<?php

namespace Entities;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class Produto
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    protected $id;

    /**
     * @ORM\ManyToOne(targetEntity="User", inversedBy="produtos")
     */
    protected $categoria;

    /**
     * @ORM\Column(type="string")
     */
    protected $nome;
}

class Categoria :

<?php

namespace Entities;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class Categoria
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    protected $id;

    /**
     * @ORM\OneToMany(targetEntity="Phone", mappedBy="user")
     */
    protected $produtos;

    /**
     * @ORM\Column(type="string")
     */
    protected $nome;
}

Some important points:

I prefer to use bi-directional relationships in almost 100% of cases, so I do not need to create custom queries in DQL. After generating the stubs (methods of the above classes), you can search for the category of a product with $produto->getCategoria() , in the same way that you search for products in a category with $categoria->getProdutos() .
Although the $categoria attribute implies creating the categoria_id column in the product table, it will not happen because you declared the $produtos attribute in the category table; it's just a relationship information.
In the example above, the categoria_id column of Produto will be null because it is Doctrine default. For the column to be non-null, simply add the annotation @ORM\JoinColumn(nullable=false) in the $categoria attribute.