Question

我试图通过一对多的关系坚持3个实体，但我无法做到正确。这就是我所拥有的：

@Entity
@Table(name = "tb_person")
public class Person {
    @Id
    @SequenceGenerator(name = "my_seq", sequenceName = "pk_seq", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "my_seq")
    @Column(name="person_id")
    private long personId;

    @OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
    @JoinColumn(name = "person_id", referencedColumnName = "person_id")
    private List<Phone> phones;
}


@Entity
@IdClass(PersonBrandId.class)
@Table(name = "tb_person_phone")
public class Phone {
     @Id
     @Column(name = "retailer_id")
     private long personId;

     @Id
     @Column(name = "brand_code")
     private String brandCode;

     @OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
     @JoinColumns({
        @JoinColumn(name = "brand_code", referencedColumnName = "brand_code", insertable = false, updatable = false),
        @JoinColumn(name = "person_id", referencedColumnName = "person_id", insertable = false, updatable = false)})
     List<Mobile> mobiles;

     ...other fields...
}

@Entity
@Table(name = "tb_mobile")
public class Mobile {
    @Id
    @SequenceGenerator(name = "my_seq2", sequenceName = "pk_seq2", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "my_seq2")
    @Column(name="mobile_id")
    private long mobileId;

    @Column(name = "person_id")
    private long personId;

    ...other fields...
}

所以，我想要达到的目的只是坚持使用Person，因为级联，Phone和Mobile将自动保留。例如：

Person person = new Person();
Phone phone = new Phone();
Mobile mobile = new Mobile();
phone.getMobiles().add(mobile);
person.getPhones().add(phone);

em.persist(person);

问题是我收到错误，说tb_person_phone.person_id不能为空。

关系是单向的，所以我没有添加ManyToOne端。

为了回答一些评论：

我只使用JPA

关系如下：

人可以有多个电话。

手机具有复合主键：

   - person_id in Person

   - brand_code in Brand (a table with a list of brands)

移动设备具有主键：mobile_id

  has two FK:

   - person_id and brand_code both referencing the table Phone

用于生成表的SQL：

CREATE TABLE "TB_PERSON"
(   "PERSON_ID" NUMBER NOT NULL ENABLE, 
"PERSON_NAME" VARCHAR2(100 BYTE) NOT NULL ENABLE, 
 CONSTRAINT "PERSON_PK" PRIMARY KEY ("PERSON_ID")
);


CREATE TABLE "TB_PERSON_PHONE" 
(   "PERSON_ID" NUMBER NOT NULL ENABLE, 
    "BRAND_CODE" VARCHAR2(30 BYTE) NOT NULL ENABLE, 
    "ATTR1" VARCHAR2(1 BYTE), 
    "ATTR2" VARCHAR2(100 BYTE), 
 CONSTRAINT "PERSON_PHONE_PK" PRIMARY KEY ("PERSON_ID", "BRAND_CODE")
 FOREIGN KEY ("PERSON_ID")
  REFERENCES "TB_PERSON" ("PERSON_ID") ENABLE, 
 FOREIGN KEY ("BRAND_CODE")
  REFERENCES "TB_BRAND" ("BRAND_CODE") ENABLE
);


CREATE TABLE "TB_MOBILE" 
(   "MOBILE_ID" NUMBER NOT NULL ENABLE, 
"PERSON_ID" NUMBER NOT NULL ENABLE, 
"BRAND_CODE" VARCHAR2(30 BYTE) NOT NULL ENABLE, 
"NUMBER" VARCHAR2(30 BYTE) NOT NULL ENABLE, 
"ATTR1" VARCHAR2(100 BYTE), 
"ATTR2" VARCHAR2(100 BYTE), 
 CONSTRAINT "MOBILE_PK" PRIMARY KEY ("MOBILE_ID"),
 CONSTRAINT "MOBILE_UQ" UNIQUE ("NUMBER", "PERSON_ID", "BRAND_CODE")
 USING INDEX (CREATE UNIQUE INDEX "MOBILE_UQ_IDX" ON "TB_MOBILE" ("NUMBER",       "PERSON_ID", "BRAND_CODE"),
 FOREIGN KEY ("PERSON_ID", "BRAND_CODE")
  REFERENCES "TB_PERSON_PHONE" ("PERSON_ID", "BRAND_CODE") ENABLE
 );

Answer 1

为移动和电话实体的主键设置@GeneratedValue(strategy = GenerationType.AUTO)。

Answer 2

您正在使用人员ID作为电话类

中的标识符

@Id
 @Column(name = "retailer_id")
 private long personId;

将另一列设为Id并添加一些生成ID策略或

 Person person = new Person();

 em.persist(person); //<

 Phone phone = new Phone();
 Mobile mobile = new Mobile();
 phone.getMobiles().add(mobile);
 person.getPhones().add(phone);

 phone.setPersonId(person.getId()); // <

 em.persist(person);

JPA单向一对多关系仍然存在

2 个答案: