有:

class Container {

    @Id
    @Column(name="id")
    protected long id;

    @OneToMany
    @JoinColumn(name="container_id", nullable=false)
    protected Collection<Content> contents = new ArrayList<Content>();

}

class Content {

    @Id
    @Column(name="id")
    protected long id;

    @Column(name="link_id")
    protected long linkId;

}

哪些JPQL查询将获得具有某些ID和某些链接的容器中的内容实体?

有帮助吗?

解决方案

如果不进行双向协会,您可以做:

SELECT c 
FROM Content c, Container container 
WHERE c MEMBER OF container.contents AND c.linkId = :linkId AND container.id = :containerId 

但是,使协会双向更容易:

SELECT c from Content c 
WHERE c.container.id = :containerId AND c.linkId = :linkId

并且生成的SQL看起来更好(并且更有效)。

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