Join 原则2.1:联接节内的嵌套查询
我在构造一个条令查询(在一个Symfony项目中)时遇到了很多麻烦,我刚刚完成了它,它可以工作,但我想征求您的意见,我不确定我的解决方案是否是最好的 简单地说,我有3个SQL表:Workshop、News和Comment。他们中的最后两人与Workshop有着千丝万缕的关系 我的目标是在一个页面上显示研讨会实体以及相关的新闻和评论实体。让事情复杂一点,我只需要显示最后5条新闻和评论实体。当然,这应该在一个查询中完成(作为一个故障排除,到目前为止我一直在使用延迟加载) 我已经成功地进行了本机查询:Join 原则2.1:联接节内的嵌套查询,join,symfony,doctrine-orm,left-join,nested-queries,Join,Symfony,Doctrine Orm,Left Join,Nested Queries,我在构造一个条令查询(在一个Symfony项目中)时遇到了很多麻烦,我刚刚完成了它,它可以工作,但我想征求您的意见,我不确定我的解决方案是否是最好的 简单地说,我有3个SQL表:Workshop、News和Comment。他们中的最后两人与Workshop有着千丝万缕的关系 我的目标是在一个页面上显示研讨会实体以及相关的新闻和评论实体。让事情复杂一点,我只需要显示最后5条新闻和评论实体。当然,这应该在一个查询中完成(作为一个故障排除,到目前为止我一直在使用延迟加载) 我已经成功地进行了本机查询:
SELECT *
FROM Workshop w
LEFT JOIN (
SELECT * FROM News ORDER BY id DESC LIMIT 0, 5
) n ON w.id = n.workshop_id
LEFT JOIN (
SELECT * FROM Comment ORDER BY id DESC LIMIT 0, 5
) c ON w.id = c.workshop_id
WHERE w.id = 1 -- Random ID as an exemple
在此之后,我想将其转换为DQL,但这种语言不支持FROM和JOIN节中的嵌套查询
我最后的选择是使用本机查询。。。过了一段时间,我在车间存储库中获得了以下结果:
<?php
public function getWorkshopWithAllContent()
{
$rsm = new ResultSetMappingBuilder($this->_em);
$rsm->addRootEntityFromClassMetadata('FON\WorkshopBundle\Entity\Workshop', 'w', array(
'id' => 'wId'
));
$rsm->addJoinedEntityFromClassMetadata('FON\WorkshopBundle\Entity\News', 'n', 'w', 'news', array(
'id' => 'nId',
'title' => 'nTitle',
'content' => 'nContent',
'pubDatetime' => 'nPubDatetime',
'validated' => 'nValidated',
'workshop_id' => 'nWorkshop_id'
));
$rsm->addJoinedEntityFromClassMetadata('FON\WorkshopBundle\Entity\Comment', 'c', 'w', 'comments', array(
'id' => 'cId',
'title' => 'cTitle',
'content' => 'cContent',
'pubDatetime' => 'cPubDatetime',
'validated' => 'cValidated',
'workshop_id' => 'cWorkshop_id'
));
$query = $this->_em->createNativeQuery(
'SELECT '.
'w.id wId, w.town, w.description, w.zipcode, w.address, '.
'n.id nId, n.title nTitle, n.content nContent, n.pubDatetime nPubDatetime, n.validated nValidated, n.workshop_id nWorkshop_id, '.
'c.id cId, c.title cTitle, c.content cContent, c.pubDatetime cPubDatetime, c.validated cValidated, c.workshop_id cWorkshop_id '.
'FROM Workshop w '.
'LEFT JOIN ( '.
' SELECT * FROM News ORDER BY id DESC LIMIT 0, 5 '.
') n ON w.id = n.workshop_id '.
'LEFT JOIN ( '.
' SELECT * FROM Comment ORDER BY id DESC LIMIT 0, 5 '.
') c ON w.id = c.workshop_id '.
'WHERE w.id = 1 ',
$rsm
);
return $query->getOneOrNullResult();
}
就这样!我现在的问题是:有更好的解决方案吗?我的真的很长,我很惊讶条令没有想到解决办法
解决这个问题的一个永久方法是重命名表中的所有列,但我想知道在此之前是否有更简单的解决方案
谢谢。Doctrine的连接界面很自然,但它的处理相当隐蔽,因此简单地尝试扩展sql有时会让您绊倒。您没有显示实体结构,所以我猜车间看起来像: YAML(我的偏好): Dotcrine句柄与sql中显式指定的id匹配。查看更多优化查询的方法
<?php
public function getWorkshopWithAllContent()
{
$rsm = new ResultSetMappingBuilder($this->_em);
$rsm->addRootEntityFromClassMetadata('FON\WorkshopBundle\Entity\Workshop', 'w');
$rsm->addJoinedEntityFromClassMetadata('FON\WorkshopBundle\Entity\News', 'n', 'w', 'news');
$rsm->addJoinedEntityFromClassMetadata('FON\WorkshopBundle\Entity\Comment', 'c', 'w', 'comments');
$query = $this->_em->createNativeQuery(
'SELECT * '.
'FROM Workshop w '.
'LEFT JOIN ( '.
' SELECT * FROM News ORDER BY id DESC LIMIT 0, 5 '.
') n ON w.id = n.workshop_id '.
'LEFT JOIN ( '.
' SELECT * FROM Comment ORDER BY id DESC LIMIT 0, 5 '.
') c ON w.id = c.workshop_id '.
'WHERE w.id = 1 ',
$rsm
);
return $query->getOneOrNullResult();
}
The column 'id' conflicts with another column in the mapper.
Workshop:
type: entity
<< other fields >>
manyToOne:
news:
targetEntity: News
comment:
targetEntity: Comment
class Workshop {
//... << other fields >>
/**
* @ManyToOne(targetEntity="News")
* @JoinColumn(name="news_id", referencedColumnName="id")
*/
private $comment;
/**
* @ManyToOne(targetEntity="Comment")
* @JoinColumn(name="comment_id", referencedColumnName="id")
*/
private $comment;
//...
}
public function getWorkshopWithAllContent($id){
$qb= $this->_em->createQueryBuilder('w');
$qb->leftJoin('w.news', 'n')
->leftJoin('w.comment', 'c')
->andWhere($qb->expr()->eq('w.id',$id));
return $qb->getQuery()->getResult();
}