如何设置带有注释的映射以获得比现在更少的查询？

Question

如何设置带有注释的映射以获得比现在更少的查询？ 我只需要读取数据。

...
private Long id;
private String firstName;
private String lastName;
private Address address;
private Set<Office> offices = new HashSet<Office>();
private Map<Office, Position> positions = new HashMap<Office, Position>();
private Office office;
    ...
    @OneToOne
    @JoinColumn(name = "ADDRESS_ID")
    public Address getAddress() {
        return address;
    }

    @ManyToMany(fetch = FetchType.EAGER, targetEntity = Office.class)
    @JoinTable(name = "H_OFFICE_EMPLOYEE",
        joinColumns = {@JoinColumn(name = "EMPLOYEE_ID")},
        inverseJoinColumns = {@JoinColumn(name = "OFFICE_ID")})
    public Set getOffices() {
        return offices;
    }

    @ManyToMany(targetEntity = Position.class)
    @JoinTable(name = "H_OFFICE_EMPLOYEE",
        joinColumns = {@JoinColumn(name = "EMPLOYEE_ID")},
        inverseJoinColumns = {@JoinColumn(name = "POSITION_ID")})
    @MapKeyManyToMany(joinColumns = @JoinColumn(name = "OFFICE_ID"), targetEntity = Office.class)
    public Map getPositions() {
        return positions;
    }
    ...

当获得 1 名员工（以及他的地址、城市、国家、他工作的公司、每个办公室（他工作的地方）的员工数）时，我会在控制台中收到下一个查询：

Hibernate: select employee0_.EMPLOYEE_ID as...
Hibernate: select address0_.ADDRESS_ID as...
Hibernate: select offices0_.EMPLOYEE_ID as...
Hibernate: select positions0_.EMPLOYEE_ID as...
Hibernate: select employees0_.OFFICE_ID as...
Hibernate: select offices0_.EMPLOYEE_ID as...
Hibernate: select employees0_.OFFICE_ID as...
Hibernate: select positions0_.EMPLOYEE_ID as...

我必须在映射中更改哪些内容才能减少查询？

Answer 1

您需要设置要加入的获取类型，如 Hibernate 文档。