在有区别的表格中

Question

如何从一位特定作者中选择所有项目？它可能这样吗？或者如果我想要很多项目类型和项目包(项目包含很多项目),我该如何编辑实体？

项目

/**
 * @ORM\Table()
 * @ORM\Entity
 * @ORM\InheritanceType("JOINED")
 * @ORM\DiscriminatorColumn(name="discr", type="string")
 * @ORM\DiscriminatorMap({
 * "cd"   = "ItemCD",
 * "dvd"   = "ItemDVD",
 * "pack" = "ItemPack",
 * })
 */
class Item
{

    /**
     * @ORM\Column(name="id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    private $id;

    /**
     * @ORM\Column(name="name", type="string", length=250, nullable=false)
     */
    private $name;

}

ItemCD

/**
 * @ORM\Table()
 * @ORM\Entity
 */
class ItemCD extends Item
{

    /**
     * @ORM\ManyToOne(targetEntity="Author", inversedBy="item")
     * @ORM\JoinColumn(name="author_id", referencedColumnName="id")
     */
    private $author;

}

ItemDVD

/**
 * @ORM\Table()
 * @ORM\Entity
 */
class ItemDVD extends Item
{

    /**
     * @ORM\ManyToOne(targetEntity="Author", inversedBy="item")
     * @ORM\JoinColumn(name="author_id", referencedColumnName="id")
     */
    private $author;

}

ItemPack

/**
 * @ORM\Table()
 * @ORM\Entity
 */
class ItemPack extends Item
{

    /**
     * @ORM\ManyToMany(targetEntity="Item", inversedBy="item")
     * @ORM\JoinTable()
     */
    private $items;

}

作者

/**
 * @ORM\Table()
 * @ORM\Entity
 */
class Author
{

    /**
     * @ORM\Column(name="id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     *
     */
    private $id;

    /**
     * @ORM\Column(name="name", type="string", length=250, nullable=false)
     */
    private $name;

}

Answer 1

您将不得不查询特定元素.这是一个已知(并且想要)的限制,因为DQL是一种静态类型语言:请参阅http://www.doctrine-project.org/jira/browse/DDC-16

相关:如何访问doctrine2/dql查询中继承表中的字段

使用解决方法处理此问题的方法是在DQL中使用2个子查询:

SELECT
    i
FROM
    Item i
WHERE
    i.id IN(
        SELECT 
            i2.id
        FROM
            ItemDvd i2
        WHERE
            i2.author = :author
    )
    OR
    i.id IN(
        SELECT
            i3.id
        FROM
            ItemCd i3
        WHERE
            i3.author = :author
    )

如您所见,您必须手动提取每个可能子类型的标识符.

编辑:要获取给定作者的所有包(以及单个DVD或CD),查询会变得更糟:

SELECT
    i
FROM
    Item i
WHERE
    i.id IN(
        SELECT 
            i2.id
        FROM
            ItemDvd i2
        WHERE
            i2.author = :author
    )
    OR
    i.id IN(
        SELECT
            i3.id
        FROM
            ItemCd i3
        WHERE
            i3.author = :author
    )
    OR
    i.id IN(
        SELECT
            i4.id
        FROM
            ItemPack i4
        JOIN
            i4.items i5
        WHERE
            i5.id IN (
                SELECT
                    i6.id
                FROM
                    Item i6
                WHERE
                    i6.id IN(
                        SELECT 
                            i7.id
                        FROM
                            ItemDvd i7
                        WHERE
                            i7.author = :author
                    )
                    OR
                    i6.id IN(
                        SELECT
                            i8.id
                        FROM
                            ItemCd i8
                        WHERE
                            i8.author = :author
                    )
            )
    )