Question

我创建了两个表，即abc和def，我已经使用注释生成了pojo类，但是当我尝试执行项目时，我正在获得mapping异常。任何人都可以告诉我如何为串行nuber作为主键和外键（oneToMany）的表编写pojo。

CREATE TABLE abc  
(  
abc_id serial NOT NULL,  
abc_name character varying(30),    
CONSTRAINT abc_pkey PRIMARY KEY (abc_id)  
)  
WITH (  
OIDS=FALSE  
);  
ALTER TABLE abc  
OWNER TO postgres;  


CREATE TABLE def
(
def_id serial NOT NULL,
abc_id bigint NOT NULL,  
CONSTRAINT def_pkey PRIMARY KEY (def_id),
CONSTRAINT def_fkey FOREIGN KEY (abc_id)
REFERENCES abc (abc_id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH (
OIDS=FALSE
);
ALTER TABLE def
OWNER TO postgres;

和班级，Abc

@Entity  
@Table(name = "abc")  
public class Abc implements Serializable {  

private static final long serialVersionUID = 1L;    

  @Id
  @GeneratedValue(strategy=GenerationType.AUTO)
  @Column(name = "def_id")
      private BigInteger def_id;

      @Column(name = "abc_name")
      public String abc_name;

 @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name = "abc_id")
    List<Def> list;
 }

和Def

@Entity
@Table(name = "def")
public class Def implements Serializable {

private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue(strategy=GenerationType.AUTO)
  @Column(name = "def_id")
      private BigInteger def_id;

      @Column(name = "abc_id")
  public BigInteger abc_id;

 }

Answer 1

你做错了。请检查此example

您在 DEF 类中使用注释 @JoinColumn

(....)
@JoinColumn("abc_id")
public BigInteger abc_id_test;

在 ABC 上你应该使用 mappedBy 属性

@OneToMany(mappedBy="abc_id_test")
private List<Def> list;

您可以在我收录的wiki文章中找到更多信息。尝试重写此映射：）

使用@OneToMany或@ManyToMany使用串行列定位未映射的类

1 个答案: