使用ManyToMany中的findBy检查UNIQUE行是否存在任何解决方法或工作解决方案？

问题描述

所以我在这个实体中定义了这个关系：

So I've this relations defined in my entities:

class Producto
{
    /**
     * @ORM\ManyToMany(targetEntity="AppBundle\Entity\Norma", inversedBy="normasProducto", cascade={"persist"})
     * @ORM\JoinTable(name="nomencladores.norma_producto", schema="nomencladores",
     *      joinColumns={@ORM\JoinColumn(name="producto_id", referencedColumnName="id")},
     *      inverseJoinColumns={@ORM\JoinColumn(name="norma_id", referencedColumnName="id")}
     * )
     */
    protected $productoNormas;

}


class Norma
{
    /**
     * @ORM\ManyToMany(targetEntity="AppBundle\Entity\Producto", mappedBy="productoNormas", cascade={"persist"})
     */
    protected $normasProducto;
}

我正在尝试检查一个给定的对 producto_id - norma_id 已经存在，不尝试再次插入，我正在做如下：

And I'm trying to check if a given pair producto_id-norma_id already exists for not try to insert it once again and I'm doing as follow:

$exists = $em->getRepository('AppBundle:Producto')->findOneByProductoNormas($productoId);

if ($exists) {
    $status = 400;
} else {
    try {
        $producto->addProductoNormas($normaEntity);
        $em->flush();
        $response['success'] = true;
    } catch (Exception $ex) {
        $status = 400;
        $response['error'] = $ex->getMessage();
    }
}

但是我收到这个错误：

在Google上进行研究，在这里我发现可能这是一个错误点或者也许不是我们（我和报告问题的其他人）正在做错事。我找不到问题或问题在哪里，所以任何建议或帮助对我和他人来说都是好的。我唯一的想法是在RDBMS创建一个视图，然后创建一个读取它的实体，并检查记录是否已经存在，我没有其他任何想法？帮帮我？工作示例代码？

Doing a research on Google and here on SO I found that possible it's a bug as point here or perhaps is not and we (me and the others who report the issue) are doing something wrong. I can't find where the issue or problem is so any advice or help will be fine for me and others. The only idea I have in mind is create a view at RDBMS and then create a entity for read it and check if record already exists, I have not other than this one, any ideas? Help? Working example code?

推荐答案

实际上，您可以使用'database_connection'服务来检查是否存在这样的行：

Actually you can use 'database_connection' service to check if such row exists:

$this->get('database_connection')
     ->fetchColumn('select count(id) as cnt
                    from <norma_producto_table>
                    where producto_id = ? and
                          norma_id = ?', array($producto_id, $norma_id));

这比使用多对多关系方法来处理这个要容易得多。我会这样做，如果我不得不做你需要的（实际上我这样做）。

That's really easier than trying to handle this with many to many relations methods. I would do that if I had to do what you need (and actually I'm doing so).

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