原则坚持继承学说实体的php类 [英] doctrine persist php class which inherit doctrine entity

问题描述

是否有可能扩展一个学说实体的php类并持久化？

示例：

  / ** 
 * @Entity 
 * / 
 class A {
 / ** 
 * @ ORM\\ \\ ManyToMany（targetEntity =C，mappedBy =parents）
 * / 
 protected $ children; 
} 
 
 class B扩展A {
 ... 
} 
 
 class C {
 / ** 
 * @ ORM\ManyToMany（targetEntity =A，inversedBy =children）
 * / 
 protected $ parents; 
} 
 
 $ b = new B（）; 
 $ em-> persist（$ b）; 
  

解决方案

是的，这被称为继承映射，但是子类必须明确声明为 @Entity ，并且必须明确定义其映射（如果子类添加额外的属性）。

最常见的继承映射形式是单表继承，下面是Doctrine手册中的这种映射示例：

< pre class =lang-php prettyprint-override> 命名空间MyProject\Model;

/ **
* @Entity
* @InheritanceType（SINGLE_TABLE）
* @DiscriminatorColumn（name =discr，type =string）
* @DiscriminatorMap（{person=Person，employee=Employee}）
* /
class Person
{
//。 ..
}

/ **
* @Entity
* /
class员工扩展Person
{
// ...
}


Is it possible to have a php class which extends a doctrine entity and to persist it ?

example:

/**
 * @Entity
 */
class A {
  /**
   * @ORM\ManyToMany(targetEntity="C", mappedBy="parents")
   */
  protected $children;
}

class B extends A {
...
}

class C {
  /**
   * @ORM\ManyToMany(targetEntity="A", inversedBy="children")
   */
  protected $parents;
}

$b = new B();
$em->persist($b);

解决方案

Yes it's possible, this is called inheritance mapping, but the child class has to be explicitly declared as @Entity and its mapping has to be explicitly defined as well (if the child class adds extra properties).

The most common form of inheritance mapping is single table inheritance, here is an example of such mapping from the Doctrine manual:

namespace MyProject\Model;

/**
 * @Entity
 * @InheritanceType("SINGLE_TABLE")
 * @DiscriminatorColumn(name="discr", type="string")
 * @DiscriminatorMap({"person" = "Person", "employee" = "Employee"})
 */
class Person
{
    // ...
}

/**
 * @Entity
 */
class Employee extends Person
{
    // ...
}

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