正确的方式更新双向许多关系symfony2-doctrine [英] Proper way to update bidirectional Many to Many relationship symfony2-doctrine

问题描述

我做了一些研究，看完 和此 （和所有相关的问题）我仍然无法确定哪个是更新Symonfy 2学说中许多关系的正确方法。觉得应该有一个非常简单的方法，我还没有找到。

I did some research, and after reading this and this (and all the related questions) I still can't figure which is the proper way to update a many to many relationship in Symonfy 2 Doctrine. It feels that there should be a very simple way of doing it that I still haven't found.

我有这2个实体：

class student_main
{
/**
* @ORM\ManyToMany(targetEntity="support_log", inversedBy="student_main")
* @ORM\JoinTable(name="support_log_student")
**/
private $support_log;

和

class support_log
{
/**
* @ORM\ManyToMany(targetEntity="student_main", mappedBy="support_log")
**/
private $student;

我想从 support_log 开始。在控制器中，在更新操作中，我有这样的东西：

I want to start from support_log. In the controller, in the update action, I have something like that:

if ($editForm->isValid()) {        
  //add the relationship the user added
  foreach($students as $student){
    if(!$em->getRepository('mybundle:student_main')->hasSupportLog($entity,$student)){
        $entity->addstudent_main($student);//*
        }
    }
    $em->persist($entity);
    $em->flush();
    return $this->redirect($this->generateUrl('support_log_edit', array('id' => $id)));
}

当然，正如教义文档所说，我相应地改变了这个函数（addstudent_main） ：

Of course, as doctrine Documentation says, I changed that function (addstudent_main) accordingly:

public function addstudent_main(student_main $student)
{
    $student->addsupport_log($this); // the important addition
    $this->student[] = $student;
}

这工作正常，我的问题更多的是删除关系。在形式上有多重选择，用户可能会选择一些已经相关的学生，而有些学生则没有。感觉应该有一种自动的方法，但是我不得不做很多代码。

This works fine, my question is more about deleting the relationship. In the form there is a multiselect, and the user might select some students that are already related and some that don't. It feels that there should be an automatic way of doing that, but instead I had to do lots of code.

在控制器中，稍微高于我之前写的代码我把它放在那里：

In the controller, just slightly above the code I wrote before, I put that:

//delete all old relationship
foreach($idsldstudents as $idst){ //I take Id's because the doctrine collection is updating always..
            $stu=$em->getRepository('MyBundle:student_main')->find($idst);
            $stu->deletesupport_log($entity);//I had to create that method (in the entity, I do "$this->support_log->removeElement($support_log)")
            $em->persist($stu);
            $em->flush();
        }

我删除了有关实体的所有关系（当然，关心是双向关系，所以必须先在另一方面删除），然后用户选择的内容将被添加。

I delete all the relationships of the entity in question (of course, taking in care that is a bidirectional relationship, so it has to be deleted first in the other side), and then the ones that the user selected will be added.

还有其他这样做的方式，但我没有找到任何简单的方法。在所有这些方面我都有同样的问题：

There are other ways of doing that, but I haven't found any simple one. In all of them I have the same problems:

• 如果关系存在，我需要检查所有的时间


• 我需要获得旧的关系（这很困难），并与用户指出的新关系进行比较，并删除或创建相应的

有没有办法自动处理这两个问题？ （我有一种强烈的感觉，一定是 - 可能会更好地宣布关系？ - 这就是为什么我问）。

Is there a way of doing that that takes care of these 2 problems automatically? (I have a strong feeling that there must be - maybe with a better declaration of the relationship? - that's why I am asking).

提前感谢

编辑：
我的表单没什么特别之处，我想我甚至没有触及生成的代码。它显示我想要的多重选择，默认的Symfony2，您必须使用 ctrl 键来选择多个。这是代码：

My form hasn't anything special, I think I didn't even touch the generated code. It displays the multiselect that I want, the default of Symfony2, where you have to use ctrl key to select more than one. Here is the code:

public function buildForm(FormBuilder $builder, array $options)
{
    $builder           
        ->add('student')
        ... 
        ;
}

密钥依赖于这里？

推荐答案

根据教义文件，只会检查协会的拥有方面是否有变更。

According to doctrine documentation it will only check the owning side of an association for changes.

http://doctrine-orm.readthedocs.org/en/latest/reference/unitofwork -associations.html

所以最好的办法是保留更新的边界实体的含义。

So the best way is keep owning side entity assotiations updated.

在这种情况下，您必须在添加和删除方法中删除并添加student_log中的support_log

In this case you must remove and add support_log in student main in add and remove methods

class support_log
{
/**
* @ORM\ManyToMany(targetEntity="student_main", mappedBy="support_log")
**/
private $student;

public function addStudent($student) {
  $this->student[] = $student;
  $student->addSupportLog($this);
}

public function removeStudent($student) {
  $student->removeSupportLog($this);
  $this->student->removeElement($student);
}

这些都不需要修改控制器的操作。
重要的是在协会的相反方面实现这一点！

Thats all no need to modify controller actions. Important implement this at the inverse side of association!

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