我使用 symfony 3 和 doctrine,这是我的问题:
我想制作由不同数量的配料组成的菜肴。
数据库看起来像这样:
[ Dish ] <===> [ IngredientDish ] <===> [ Ingredient ]
[------] [----------------] [------------]
[- name] [- Dish ] [-name ]
[ ] [- Ingredient ] [ ]
[ ] [- quantity ] [ ]
[------] [----------------] [------------]
这是我的代码:
Dish.php
/**
* @ORM\Table(name="dish")
* @ORM\Entity(repositoryClass="AppBundle\Repository\DishRepository")
*/
class Dish
{
/**
* @ORM\OneToMany(targetEntity="AppBundle\Entity\IngredientDish",
* mappedBy="dish")
*/
private $ingredientsDish;
[...]
public function addIngredientDish(IngredientDish $ingredient)
{
$this->ingredientsDish[] = $ingredient;
return $this;
}
public function getIngredientsDish()
{
return $this->ingredientsDish;
}
}
成分.php
/**
* @ORM\Table(name="ingredient")
* @ORM\Entity(repositoryClass="AppBundle\Repository\IngredientRepository")
*/
class Ingredient
{
/**
* @ORM\OneToMany(targetEntity="AppBundle\Entity\IngredientDish",
* mappedBy="ingredient")
* @Assert\Type(type="AppBundle\Entity\IngredientDish")
*/
private $ingredientsDish;
[...]
public function addIngredientDish(IngredientDish $ingredientDish)
{
$this->ingredientDish[] = $ingredientDish;
return $this;
}
public function getingredientsDish()
{
return $this->ingredients;
}
}
IngredientDish.php
/**
* @ORM\Table(name="ingredient_dish")
* @ORM\Entity(repositoryClass="AppBundle\Repository\IngredientDishRepository")
*/
class IngredientDish
{
/**
* @ORM\Column(name="quantity", type="smallint")
* @Assert\NotBlank()
* @Assert\Length(min=1)
*/
private $quantity = 1;
/**
* @ORM\ManyToOne(targetEntity="AppBundle\Entity\Ingredient",
* inversedBy="ingredientsDish")
* @Assert\Type(type="AppBundle\Entity\Ingredient")
*/
private $ingredient;
/**
* @ORM\ManyToOne(targetEntity="AppBundle\Entity\Dish",
* inversedBy="ingredientsDish")
* @ORM\JoinColumn()
* @Assert\Type(type="AppBundle\Entity\Dish")
*/
private $dish;
public function __construct(Ingredient $ingredient, Dish $dish, $quantity = 1)
{
$this->setIngredient($ingredient);
$this->setDish($dish);
$this->setQuantity($quantity);
}
public function setQuantity($quantity)
{
$this->quantity = $quantity;
return $this;
}
public function getQuantity()
{
return $this->quantity;
}
public function setIngredient(Ingredient $ingredient)
{
$this->ingredient = $ingredient;
return $this;
}
public function getIngredient()
{
return $this->ingredient;
}
public function setDish(Dish $dish)
{
$this->dish = $dish;
return $this;
}
public function getDish()
{
return $this->dish;
}
}
我的测试代码
$em = $this->getDoctrine()->getManager();
//Get an apple pie
$dish = $em->getRepository('AppBundle:Dish')->find(6);
//Get an apple
$ingredient = $em->getRepository('AppBundle:Ingredient')->find(11);
$quantityApple = 5;
$ingredientDish = new IngredientDish($ingredient, $dish, $quantityApple);
$ingredient->addIngredientDish($ingredientDish);
$dish->addIngredientDish($ingredientDish);
$em->persist($ingredientDish);
$em->persist($dish);
$em->flush();
执行后,我有一个有趣的条目:
mysql> select * from ingredient_dish;
+----+---------------+----------+---------+
| id | ingredient_id | quantity | dish_id |
+----+---------------+----------+---------+
| 1 | 11 | 5 | 6 |
+----+---------------+----------+---------+
但是之后,如果我尝试拿到我的菜:
$dish = $em->getRepository('AppBundle:Dish')->find(6);
dump($dish->getIngredientsDish());
它没有成分:
PersistentCollection {#1180 ▼
-snapshot: []
-owner: Dish {#1146 ▶}
-association: array:15 [ …15]
-em: EntityManager {#1075 …11}
-backRefFieldName: "dish"
-typeClass: ClassMetadata {#1157 …}
-isDirty: false
#collection: ArrayCollection {#1181 ▼
-elements: [] <<<<<<<<<<<<<<<<<<<<< EMPTY
}
#initialized: false
}
我的测试代码执行后数据库不为空,所以我认为是getter出错了。 你能帮我吗,你看到什么东西是假的吗?
感谢您的帮助! :)
最佳答案
我认为一切都很好,但你被延迟加载误导了,这显然比你想象的要聪明。 ;-)
当你这样做的时候
$dish->getIngredientsDish();
您收到 PersistentCollection
,它扩展了 AbstractLazyCollection
。
但该集合仍未从 DB(!) 中提取
仔细查看您的 var_dump
结果
PersistentCollection {#1180 ▼
-snapshot: []
-owner: Dish {#1146 ▶}
-association: array:15 [ …15]
-em: EntityManager {#1075 …11}
-backRefFieldName: "dish"
-typeClass: ClassMetadata {#1157 …}
-isDirty: false
#collection: ArrayCollection {#1181 ▼
-elements: [] <<<<<<<<<<<<<<<<<<<<< EMPTY //<= yeah empty, but...
}
#initialized: false // <= it's still not initialized!
}
如您所见,initialized
属性表示集合仍未初始化(未从 DB 获取)。
只是尝试使用它。它将在第一次使用时获取集合。
关于database - 创建一个双向的多对多关联,带有额外的学说字段,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/39379829/