php 期望来自学说查询构建器的一个结果或没有结果，我应该使用什么？
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Expect one or no result from a doctrine query builder, what should I use?
提问by Faery
I have this method:
我有这个方法：
public function getMonth ($month_name)
{
$q = $this->createQueryBuilder('m');
$q->select('m')
->where('m.name = :name')
->setParameter('name', $month_name);
return $q->getQuery()->getResult();
}
From it I expect to find one month or 0 months. I use this method in this way in my Controllers:
我希望从中找到 1 个月或 0 个月。我在我的控制器中以这种方式使用这种方法：
$month = $em->getRepository('EMExpensesBundle:Month')
->getMonth($this->findMonth());
$month->setSpended($item->getPrice());
I tried this with getSingleResult()and everything was perfect untill I came across a case when no month was found and everything failed really bad!
我试过这个，getSingleResult()一切都很完美，直到我遇到一个没有找到月份的情况，一切都非常糟糕！
Then I tried with getResult(), but it returns an array and then
然后我尝试使用getResult()，但它返回一个数组，然后
$month->setSpended($item->getPrice());
is said to be called on a non-object and to fix it I should use everywhere
据说在非对象上调用并修复它我应该在任何地方使用
$month[0]->setSpended($item->getPrice());
Is there a more elegant way to achieve this without the need to add unnecesary [0] index everywhere?
有没有更优雅的方法来实现这一点，而无需在任何地方添加不必要的 [0] 索引？
回答by olegkhuss
Additionally, in Doctrine 2.1 you can use 'getOneOrNullResult'
此外，在 Doctrine 2.1 中，您可以使用“getOneOrNullResult”
回答by Sgoettschkes
If you use getSingleResult, Doctrine throws a \Doctrine\ORM\NoResultException, which you can catch and handle it. If you want to catch this directly in the Repository, I would suggest:
如果您使用getSingleResult，Doctrine 会抛出一个\Doctrine\ORM\NoResultException，您可以捕获并处理它。如果您想直接在存储库中捕获它，我建议：
public function getMonth ($month_name)
{
$q = $this->createQueryBuilder('m');
$q->select('m')
->where('m.name = :name')
->setParameter('name', $month_name);
try {
return $q->getQuery()->getResult();
}
catch(\Doctrine\ORM\NoResultException $e) {
return new Month();
}
}
Dont forget to add a use Your\Namespace\Month;or this will fail because it cannot find the Month class!
不要忘记添加 ause Your\Namespace\Month;否则会失败，因为它找不到 Month 类！
Of course you must also persist the Entity in case it is a new one. You could extend the catch block like this:
当然，您还必须保留实体，以防它是新实体。您可以像这样扩展 catch 块：
catch(\Doctrine\ORM\NoResultException $e) {
$month = new Month();
$this->_em->perist($month);
return $month;
}
You could also catch the exception in your controller, making it more transparent. But this depends on your use cases and is best solved by yourself
您还可以在控制器中捕获异常，使其更加透明。但这取决于您的用例，最好由您自己解决
