I'm using @EntityGraph to eagerly load some attributes.
However, something broke after updating from 6.1. 5. x Final to 6. x 1 . 6.Final
Suppose we have a human who can have multiple houses:
{code:java}
public class Human {
@Id
@Column(name = "ID", nullable = false, updatable = false, precision = 20)
@GeneratedValue
private BigInteger id;
@EqualsAndHashCode.Exclude
@ToString.Exclude
@OneToMany(mappedBy = "human", cascade = CascadeType.ALL)
@OnDelete(action = OnDeleteAction.CASCADE)
private Collection<House> houses;
}
{code}
When searching for a human, by ID, EntityGraph can eagerly load some attributes:
{code:java}
@EntityGraph(attributePaths = { "houses.address" })
@Query ("SELECT h FROM Human h WHERE h.id = ?1")
Human findByIdEagerHouseAddresses(Integer id);
{code}
This will create SQL with left (outer by default) joins:
{code:sql}
select h1_0.id, h2_0.human_fk, h2_0.address_fk, a1_0.id
from human h1_0
left join house h2_0 on h1_0.id = h2_0.human_fk
left join address a1_0 on a1_0.id = h2_0.address_fk where h1_0.id in (?)
{code}
This is acceptable because I will get the human even if they don't have a house.
However, if the address field in the house has the @Id annotation, the outer join will change to "inner":
{code:java}
@Entity
public class House {
@Id
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "human_fk", nullable = false, updatable = false)
private Human human;
@Id // THIS ANNOTATION WAS ADDED
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "address_fk", nullable = false, updatable = false)
private Address address;
}
{code}
{code:sql}
select h1_0.id, h2_0.human_fk, h2_0.address_fk, a1_0.id
from human h1_0
left join house h2_0 on h1_0.id = h2_0.human_fk
join address a1_0 on a1_0.id = h2_0.address_fk where h1_0.id in (?)
{code}
If a human does not have a house, the query returns nothing due to the inner join, which seems like a bug.
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