blocks|key|1937655|text|您不能查询@MappedSuperClass。在6.1。映射超类中也提到了这一点|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1937656|映射的超类不能是实体，它不是可查询的和持久的。|blockquote|1937657|这意味着您必须将目标实体更改为可查询的对象，或者必须将MachineHasPart更改为实体并更改为单表继承。|1937658|当我查看您的数据库结构时，我建议将您的Machine实体更改为三个独立的部件关系。一个用于皮带，一个用于气缸，另一个用于齿轮。|1937659|然后，您将有三个方法(+getBelts、getCylinders和getGears+)，而不是泛型的getCylinders。|1937660|如果这真的不是你想要的，那么你可以留下评论。|1937661|更新|1937662|您也可以通过类继承来解决这个问题。首先，创建一个同时也是一个实体的基类Part，并在其他类Belt、Cylinder和Gear中使用它。|1937663|部件：|BOLD|1937664|<?php

namespace+Machine\Entity;

use+Doctrine\ORM\Mapping+as+ORM;

/**
+*+Part
+*
+*+@ORM\Entity
+*+@ORM\Table("part")
+*+@ORM\InheritanceType("SINGLE_TABLE")
+*+@ORM\DiscriminatorColumn(name="discriminator",+type="string")
+*+@ORM\DiscriminatorMap({
+*+++++"part"+=+"Part",
+*+++++"gear"+=+"Gear",
+*+++++"cylinder"+=+"Cylinder",
+*+++++"belt"+=+"Belt",
+*+})
+*+@property+int+$id
+*/
class+Part
{
++++/**
+++++*+@ORM\Id
+++++*+@ORM\Column(type="integer")
+++++*+@ORM\GeneratedValue(strategy="AUTO")
+++++*/
++++protected+$id;

++++/**
+++++*+@var+Machine
+++++*+@ORM\ManyToOne(targetEntity="Machine\Entity\Machine",+inversedBy="parts")
+++++*+@ORM\JoinColumn(name="machine_id",+referencedColumnName="id",+nullable=true)
+++++*/
++++protected+$machine;

++++/**
+++++*+Get+id.
+++++*
+++++*+@return+int
+++++*/
++++public+function+getId()
++++{
++++++++return+$this->id;
++++}

++++/**
+++++*+Set+id.
+++++*
+++++*+@param+int+$id
+++++*+@return+self
+++++*/
++++public+function+setId($id)
++++{
++++++++$this->id+=+$id;

++++++++return++$this;
++++}

++++//...+add+setters+and+getters+for+machine+as+normal+...
}|code-block|syntax|javascript|1937665|在其他部分中扩展这个类：|1937666|带：|1937667|<?php

namespace+Machine\Entity;

/**
+*+Belt
+*
+*+@ORM\Entity
+*/
class+Belt+extends+Part
{
}|1937668|气缸：|1937669|<?php

namespace+Machine\Entity;

/**
+*+Cylinder
+*
+*+@ORM\Entity
+*/
class+Cylinder+extends+Part
{

}|1937670|齿轮：|1937671|<?php

namespace+Machine\Entity;

/**
+*+Gear
+*
+*+@ORM\Entity
+*/
class+Gear+extends+Part
{

}|1937672|现在，在您的机器中，相关部件如下所示。|1937673|机器：|1937674|<?php

namespace+Machine\Entity;

use+Doctrine\ORM\Mapping+as+ORM;
use+Doctrine\Common\Collections\Collection;
use+Doctrine\Common\Collections\ArrayCollection;

/**
+*+Machine
+*
+*+@ORM\Entity
+*+@ORM\Table("machine")
+*+@property+int+$id
+*/
class+Machine
{
++++/**
+++++*+@ORM\Id
+++++*+@ORM\Column(type="integer")
+++++*+@ORM\GeneratedValue(strategy="AUTO")
+++++*/
++++protected+$id;

++++/**
+++++*+Get+id.
+++++*
+++++*+@return+int
+++++*/
++++public+function+getId()
++++{
++++++++return+$this->id;
++++}

++++/**
+++++*+Set+id.
+++++*
+++++*+@param+int+$id
+++++*+@return+self
+++++*/
++++public+function+setId($id)
++++{
++++++++$this->id+=+$id;

++++++++return++$this;
++++}

++++/**
+++++*+@var+Collection
+++++*+@ORM\OneToMany(targetEntity="Machine\Entity\Part",+mappedBy="machine")
+++++*/
++++protected+$parts;

++++public+function+__constuct()
++++{
++++++++$parts+=+new+ArrayCollection();
++++}

++++/**
+++++*
+++++*+@return+Collection
+++++*/
++++public+function+getParts()
++++{
++++++++return+$this->parts;
++++}

++++//...+add+setters+and+getters+for+parts+as+normal+...
}|1937675|1937676|entityMap|0|LINK|mutability|MUTABLE|url|http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#mapped-superclasses|1|http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#single-table-inheritance^0|5|H|O|8|0|0|0|R|E|1E|4|1|0|J|7|0|C|8|L|C|Y|8|1F|C|0|0|0|Z|4|19|4|1E|8|1N|4|0|0|3|0|0|0|0|2|0|0|0|3|0|0|0|3|0|0|0|0|3|0|0|0^^$0|@$1|2|3|4|5|6|7|1X|8|@$9|1Y|A|1Z|B|C]]|D|@$9|20|A|21|1|22]]|E|$]]|$1|F|3|G|5|H|7|23|8|@]|D|@]|E|$]]|$1|I|3|J|5|6|7|24|8|@$9|25|A|26|B|C]]|D|@$9|27|A|28|1|29]]|E|$]]|$1|K|3|L|5|6|7|2A|8|@$9|2B|A|2C|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|2D|8|@$9|2E|A|2F|B|C]|$9|2G|A|2H|B|C]|$9|2I|A|2J|B|C]|$9|2K|A|2L|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|2M|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|2N|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|2O|8|@$9|2P|A|2Q|B|C]|$9|2R|A|2S|B|C]|$9|2T|A|2U|B|C]|$9|2V|A|2W|B|C]]|D|@]|E|$]]|$1|U|3|V|5|6|7|2X|8|@$9|2Y|A|2Z|B|W]]|D|@]|E|$]]|$1|X|3|Y|5|Z|7|30|8|@]|D|@]|E|$10|11]]|$1|12|3|13|5|6|7|31|8|@]|D|@]|E|$]]|$1|14|3|15|5|6|7|32|8|@$9|33|A|34|B|W]]|D|@]|E|$]]|$1|16|3|17|5|Z|7|35|8|@]|D|@]|E|$10|11]]|$1|18|3|19|5|6|7|36|8|@$9|37|A|38|B|W]]|D|@]|E|$]]|$1|1A|3|1B|5|Z|7|39|8|@]|D|@]|E|$10|11]]|$1|1C|3|1D|5|6|7|3A|8|@$9|3B|A|3C|B|W]]|D|@]|E|$]]|$1|1E|3|1F|5|Z|7|3D|8|@]|D|@]|E|$10|11]]|$1|1G|3|1H|5|6|7|3E|8|@]|D|@]|E|$]]|$1|1I|3|1J|5|6|7|3F|8|@$9|3G|A|3H|B|W]]|D|@]|E|$]]|$1|1K|3|1L|5|Z|7|3I|8|@]|D|@]|E|$10|11]]|$1|1M|3|13|5|6|7|3J|8|@]|D|@]|E|$]]|$1|1N|3|-4|5|6|7|3K|8|@]|D|@]|E|$]]]|1O|$1P|$5|1Q|1R|1S|E|$1T|1U]]|1V|$5|1Q|1R|1S|E|$1T|1W]]]]

You cannot query a <code>@MappedSuperClass</code>. This is also mentioned in the <a href="http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#mapped-superclasses" rel="nofollow">Doctrine2 documentation in chapter 6.1. Mapped Superclasses</a>:

<blockquote>
 A mapped superclass cannot be an entity, it is not query-able and persistent 
</blockquote>

This means you have to either change the target entity to something queryable or you have to make <code>MachineHasPart</code> to a entity and change to <a href="http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#single-table-inheritance" rel="nofollow">single table inheritance</a>. 

When I look at your database structure I would suggest changing your <code>Machine</code> entity to have three independent relationships for the parts. One for Belt, one for Cylinder and one for Gear.

Then instead of a generic <code>getParts</code> you will have three methods <code>getBelts</code>, <code>getCylinders</code> and <code>getGears</code>.

If that is really not what you want then you can leave a comment.

<h2>UPDATE</h2>

You can solve it also with class inheritance. First make a base class <code>Part</code> that is also an entity and use it in the other classes <code>Belt</code>, <code>Cylinder</code> and <code>Gear</code>:

Part:

<pre><code>&lt;?php

namespace Machine\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Part
 *
 * @ORM\Entity
 * @ORM\Table("part")
 * @ORM\InheritanceType("SINGLE_TABLE")
 * @ORM\DiscriminatorColumn(name="discriminator", type="string")
 * @ORM\DiscriminatorMap({
 * "part" = "Part",
 * "gear" = "Gear",
 * "cylinder" = "Cylinder",
 * "belt" = "Belt",
 * })
 * @property int $id
 */
class Part
{
 /**
 * @ORM\Id
 * @ORM\Column(type="integer")
 * @ORM\GeneratedValue(strategy="AUTO")
 */
 protected $id;

 /**
 * @var Machine
 * @ORM\ManyToOne(targetEntity="Machine\Entity\Machine", inversedBy="parts")
 * @ORM\JoinColumn(name="machine_id", referencedColumnName="id", nullable=true)
 */
 protected $machine;

 /**
 * Get id.
 *
 * @return int
 */
 public function getId()
 {
 return $this-&gt;id;
 }

 /**
 * Set id.
 *
 * @param int $id
 * @return self
 */
 public function setId($id)
 {
 $this-&gt;id = $id;

 return $this;
 }

 //... add setters and getters for machine as normal ...
}
</code></pre>

Extend this class in your other parts:

Belt:

<pre><code>&lt;?php

namespace Machine\Entity;

/**
 * Belt
 *
 * @ORM\Entity
 */
class Belt extends Part
{
}
</code></pre>

Cylinder:

<pre><code>&lt;?php

namespace Machine\Entity;

/**
 * Cylinder
 *
 * @ORM\Entity
 */
class Cylinder extends Part
{

}
</code></pre>

Gear:

<pre><code>&lt;?php

namespace Machine\Entity;

/**
 * Gear
 *
 * @ORM\Entity
 */
class Gear extends Part
{

}
</code></pre>

Now in your machine relate to the parts like as follows.

Machine:

<pre><code>&lt;?php

namespace Machine\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\Collection;
use Doctrine\Common\Collections\ArrayCollection;

/**
 * Machine
 *
 * @ORM\Entity
 * @ORM\Table("machine")
 * @property int $id
 */
class Machine
{
 /**
 * @ORM\Id
 * @ORM\Column(type="integer")
 * @ORM\GeneratedValue(strategy="AUTO")
 */
 protected $id;

 /**
 * Get id.
 *
 * @return int
 */
 public function getId()
 {
 return $this-&gt;id;
 }

 /**
 * Set id.
 *
 * @param int $id
 * @return self
 */
 public function setId($id)
 {
 $this-&gt;id = $id;

 return $this;
 }

 /**
 * @var Collection
 * @ORM\OneToMany(targetEntity="Machine\Entity\Part", mappedBy="machine")
 */
 protected $parts;

 public function __constuct()
 {
 $parts = new ArrayCollection();
 }

 /**
 *
 * @return Collection
 */
 public function getParts()
 {
 return $this-&gt;parts;
 }

 //... add setters and getters for parts as normal ...
}
</code></pre>

Extend this class in your other parts:

blocks|key|1937746|text|在第6.1章中的Doctrine2文档。映射超类中进一步阅读(由@Wilt引用)：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1937747|..。此外，只有当映射的超类目前只在一个实体中使用时，才有可能出现多到多的关联.|blockquote|1937748|这意味着在这种情况下ORM映射没有帮助。我不能同时通过一个MachineHasCylinder、MachineHasBelt和MachineHasGear三个实体通过MappedSupperclass收集数据。我认为使用DQL或原生SQL是解决这个问题的唯一方法。|1937749|entityMap|0|LINK|mutability|MUTABLE|url|http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#mapped-superclasses|1|http://doctrine-orm.readthedocs.org/en/latest/reference/dql-doctrine-query-language.html|2|http://doctrine-orm.readthedocs.org/en/latest/reference/native-sql.html^0|1|N|0|0|0|32|3|1|36|5|2|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$]]|$1|G|3|H|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]|$A|13|B|14|1|15]]|C|$]]|$1|I|3|-4|5|6|7|16|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]|S|$5|L|M|N|C|$O|T]]]]

Reading further in the <a href="http://doctrine-orm.readthedocs.org/en/latest/reference/inheritance-mapping.html#mapped-superclasses" rel="nofollow">Doctrine2 documentation in chapter 6.1. Mapped Superclasses</a> (referred to by @Wilt): 

<blockquote>
 ... Furthermore Many-To-Many associations are only possible if the mapped superclass is only used in exactly one entity at the moment...
</blockquote>

This means in this case the ORM mapping doesn't help. I cannot gather the data of all three entities MachineHasCylinder, MachineHasBelt and MachineHasGear through a MappedSupperclass at the same time.
I think using <a href="http://doctrine-orm.readthedocs.org/en/latest/reference/dql-doctrine-query-language.html" rel="nofollow">DQL</a> or <a href="http://doctrine-orm.readthedocs.org/en/latest/reference/native-sql.html" rel="nofollow">Native SQL</a> is the only solution for this problem.

I am new to Doctrine2 and trying to create entities for the following DB structure:
<a href="https://i.stack.imgur.com/22ZgE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/22ZgE.png" alt="enter image description here"></a>

I want to have all machine parts as an array in one attribute of the machine class. I tried this:

<pre><code>class Machine {
 ....
 /**
 * @var array
 * @ORM\OneToMany(targetEntity="MachineHasPart", mappedBy="machine", cascade={"persist", "remove"}, orphanRemoval=TRUE)
 */
 private $parts;
 ....

 public function getParts () {
 return array_map(
 function ($machineHasPart) {
 return $machineHasPart-&gt;getPart();
 },
 $this-&gt;parts-&gt;toArray()
 );
 }
}
</code></pre>

Where <code>MachineHasPart</code> is a <code>@MappedSuperclass</code> for the intermediate entities/tables (like <code>machineHasCylinder</code> etc), but it failed with: 

<blockquote>
 An exception occurred while executing 'SELECT FROM machineHasPart t0'.
</blockquote>

Should I restructure my database to use ORM here? Or there is a solution for my case?

Doctrine 2 many-to-many with MappedSuperclass in Zend framework 2

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我对Doctrine2很陌生，并试图为以下DB结构创建实体：​我希望在机器类的一个属性中将所有机器部件作为数组。我试过这个：class Machine {    ....    /**     * @var array     * @ORM\OneToMany(targetEntity="MachineHasPart"...

问在Zend框架2中使用MappedSuperclass的多对多的原则
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问在Zend框架2中使用MappedSuperclass的多对多的原则EN