Has:
class Container {
@Id
@Column(name="id")
protected long id;
@OneToMany
@JoinColumn(name="container_id", nullable=false)
protected Collection<Content> contents = new ArrayList<Content>();
}
and
class 开发者_如何学编程Content {
@Id
@Column(name="id")
protected long id;
@Column(name="link_id")
protected long linkId;
}
What JPQL query will get Content entities that are in Container with certain id and with certain linkId?
Without making the association bidirectional, you could do:
SELECT c
FROM Content c, Container container
WHERE c MEMBER OF container.contents AND c.linkId = :linkId AND container.id = :containerId
But it would be easier to make the association bidirectional:
SELECT c from Content c
WHERE c.container.id = :containerId AND c.linkId = :linkId
And the generated SQL looks better (and more efficient).
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