Postgres Hibernate 主键生成问题

Question

我正在尝试使用 Hibernate ORM 在 Employee table 中插入一条记录，但不断收到错误消息：

org.hibernate.AssertionFailure: null id in 
com.example.helloworld.entities.Employee entry (don't flush the Session 
after an exception occurs)

如果我传递 ID 值那么它工作正常但是虽然我使用了 @GeneratedValue(strategy = GenerationType.IDENTITY) 它不会自动生成 'id'。任何帮助表示赞赏！ DB 模式和实体代码的详细信息如下所示。

数据库引擎：Postgres

ORM：休眠

我有以下两个 tables :

Table姓名员工:

Column Name |  Type      |  Length    |  Not Null  | Default
name        | Varchar    |  64        |  true      | NULL 
id          |  int8      |  19        |  true      |nextval(Employee_id::regclass)
company_id  |  int8     |19           |  true      | NULL

Table #公司

Column Name |  Type      |  Length    |  Not Null  | Default
Cname       | Varchar    |  64        |  true      | NULL 
id          |  int8      |  19        |  true      | nextval(Company_id::regclass)

 面积 |变量 |64 |真 |空

实体 Java 类以上 tables :

@Entity
@Table(name = "Employee")
public class Employee {

    public Employee() {super();}

    @Id
    @Column(name = "id", columnDefinition = "serial")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @NotNull
    private long id;

    @NotNull
    @Column(name = "company_id")
    private long company_id;

    @NotNull
    @Column(name = "name")
    private String name;

    @ManyToOne
    private Company company;

   /**
   setters and getters
   **/
}

@Entity
@Table(name = "Company")
public class Company {

    public Company() {super();}

    @Id
    @Column(name = "id", columnDefinition = "serial")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @NotNull
    private long id;

    @NotNull
    @Column(name = "area")
    private String area;

    @NotNull
    @Column(name = "cname")
    private String cname;

    @OneToMany(cascade=CascadeType.ALL)
    @JoinColumn(name="company_id")
    private Set<Employee> employees;

   /**
   setters and getters
   **/
}

Answer 1

我对 Postgres 也有同样的问题。尝试将 SequenceGenerator 添加到您的 id 字段：

@Id
@Column(name = "id", columnDefinition = "serial")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator="SEQ_EMPLOYEE")
@SequenceGenerator(name="SEQ_EMPLOYEE", sequenceName="SEQ_EMPLOYEE", allocationSize=1)
@NotNull
private long id;

将SEQ_EMPLOYEE替换为数据库中的序列名称。

Answer 2

这对我有用：

@Id
@Column(name = "id", columnDefinition = "serial")
@GeneratedValue(strategy = GenerationType.IDENTITY, generator="seq_name_generated_in_db")
@SequenceGenerator(name="seq_name_generated_in_db", sequenceName="seq_name_generated_in_db", initialValue = 1 , allocationSize=1)

Postgres Hibernate 主键生成问题

Postgres Hibernate Primary Key generation Issue

java

sql

postgresql

hibernate

hibernate-mapping