Doctrine 2 - ORM

Joining Associations in Single Inheritance Scheme

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Major Major
  • Resolution: Can't Fix
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Security Level: All
  • Labels:
    None

Description

Let's assume the following class hierarchy:

AbstractComment
SpecialComment extends AbstractComment
{
    private $specialAssociation;
}
RegularComment extends RegularComment

Now, I'd like to write a query such as:

SELECT c, a FROM AbstractComment c LEFT JOIN c.specialAssociation a

The idea is to preload the association when selecting all comments. Now, that association is only present on a sub-class of the queried class, but since it is a single table inheritance, Doctrine should be able to join it for those entities where it is present.

At the moment unfortunately, Doctrine shows an error that the association does not exist on the AbstractComment class. Also, there is no real alternative to this except moving the collection to the base class even if it does not belong there.

Activity

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Johannes Schmitt made changes -
Field Original Value New Value
Description Let's assume the following class hierarchy:

{code}
AbstractComment
SpecialComment extends AbstractComment
{
    private $specialAssociation;
}
RegularComment extends RegularComment
{/code}

Now, I'd like to write a query such as:

{code}
SELECT c, a FROM AbstractComment c LEFT JOIN c.specialAssociation a
{code}

The idea is to preload the association when selecting all comments. Now, that association is only present on a sub-class of the queried class, but since it is a single table inheritance, Doctrine should be able to join it for those entities where it is present.

At the moment unfortunately, Doctrine shows an error that the association does not exist on the AbstractComment class. Also, there is no real alternative to this except moving the collection to the base class even if it does not belong there. 		Let's assume the following class hierarchy:

{code}
AbstractComment
SpecialComment extends AbstractComment
{
    private $specialAssociation;
}
RegularComment extends RegularComment
{code}

Now, I'd like to write a query such as:

{code}
SELECT c, a FROM AbstractComment c LEFT JOIN c.specialAssociation a
{code}

The idea is to preload the association when selecting all comments. Now, that association is only present on a sub-class of the queried class, but since it is a single table inheritance, Doctrine should be able to join it for those entities where it is present.

At the moment unfortunately, Doctrine shows an error that the association does not exist on the AbstractComment class. Also, there is no real alternative to this except moving the collection to the base class even if it does not belong there.
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Benjamin Eberlei added a comment -

DQL has strict typing with regard to inheritance, this type of query is not possible.

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Benjamin Eberlei added a comment - DQL has strict typing with regard to inheritance, this type of query is not possible.
Benjamin Eberlei made changes -
Status Open [ 1 ] Resolved [ 5 ]
Resolution Can't Fix [ 7 ]
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Johannes Schmitt added a comment -

A too bad. I guess the code around inheritance is already quite complex that it does not make sense to add an exception for this case.

Do you think it would somehow (maybe manually) be possible to load collections in a batch operation? For example, something like this:

$batch = array();
foreach ($comments as $comment) {
    if ($comment instanceof SpecialComment) {
        $batch[] = $comment->getSpecialAssociation();
    }
}

$this->em->batchLoad($batch);
Show
Johannes Schmitt added a comment - A too bad. I guess the code around inheritance is already quite complex that it does not make sense to add an exception for this case. Do you think it would somehow (maybe manually) be possible to load collections in a batch operation? For example, something like this: $batch = array(); foreach ($comments as $comment) { if ($comment instanceof SpecialComment) { $batch[] = $comment->getSpecialAssociation(); } } $ this ->em->batchLoad($batch);
This list may be incomplete, as errors occurred whilst retrieving source from linked applications:
  • Request to http://www.doctrine-project.org/fisheye/ failed: Error in remote call to 'FishEye 0 (http://www.doctrine-project.org/fisheye/)' (http://www.doctrine-project.org/fisheye) [AbstractRestCommand{path='/rest-service-fe/search-v1/crossRepositoryQuery', params={query=DDC-2250, expand=changesets[-21:-1].revisions[0:29],reviews}, methodType=GET}] : Received status code 503 (Service Temporarily Unavailable)

People

  • Assignee:
    Benjamin Eberlei
    Reporter:
    Johannes Schmitt
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Dates

  • Created:
    Updated:
    Resolved: