java - Hibernate 一对一条件获取

Question

我正在使用 hibernate 在汽车和人员表之间进行一对一映射。但一个人可能有车，也可能没有车。现在，在使用 hibernate 条件从人员表中获取记录时，我只想获取那些拥有汽车的人，即仅在人员表中存在汽车表中对应条目的那些条目。如何使用 hibernate 标准/别名来完成此操作？

下面是一段代码。请帮助编写获取结果所需的条件或别名:

@Getter
@Setter
@Entity
@Table(name = "Person")
public class Person implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "Person_ID")
    private Long personId;

    @OneToOne(mappedBy = "personAsset", cascade = CascadeType.ALL)
    private Car car;
}

@Getter
@Setter
@Entity
@Table(name = "Car")
public class Car implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "Car_ID")
    private Long carId;

    @OneToOne
    @JoinColumn(name = "Person_ID")
    private Person personAsset;
}

Answer 1

您正在寻找的是@OneToOne注释上的cascadeTypeorphanRemoval=true。

这是你的类(class):

@Getter
@Setter
@Entity
@Table(name = "Car")
public class Car implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "Car_ID")
    private Long carId;

    @OneToOne(fetch=FetchType.EAGER , cascade=CascadeType.ALL, orphanRemoval=true)
    @JoinColumn(name = "Person_ID")
    private Person personAsset;
}