I have a table that hold a some relation that a commune to multiple other tables. Let’s call that Table Animal

Animal model

@Entity
public class Animal {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // other things

    @OneToOne(mappedBy = "animal" )
    private Tiger tiger;
    @OneToOne(mappedBy = "animal" )
    private Fox fox;
}

I have Tiger and Fox and others that hold the foreign key animal_id

Tiger model

@Entity
public class Tiger {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // other things

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "animal_id", referencedColumnName = "id", nullable = false)
    private Animal animal;
}

Fox is quite similary to Tiger. Everythings works but When I try to retrieve Tiger or Fox, It create a lot of SQL request.

First 1 request to Get the List of Tiger and N times animal with left join Tiger and LEFT JOIN Fox. So If I have 15 Tiger in database (db), It will trigger 16 SQL request and if I have 150 Tiger in db, it’ll trigger 151 SQL request.

I did try to create a query in my repository, but doesn’t seems to work.

@Query("SELECT t From Tiger t LEFT JOIN t.animal a LEFT JOIN a.fox f")