Postgres Hibernate Primary Key generation Issue

Question

I am trying to insert a record in Employee table with Hibernate ORM but keep getting an error as :

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

If I pass ID value then it works fine but although I have used @GeneratedValue(strategy = GenerationType.IDENTITY) it does not generate 'id' automatically. Any help is appreciated! Details on DB schema and entity code is as given below.

DB Engine: Postgres

ORM : Hibernate

I have following two tables :

Table Name Employee:

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 #Company

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

 area       |  varchar    |64          |  true      | NULL

Entity Java Classes for above 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
   **/
}

Wesley De Keirsmaeker · Accepted Answer · 2017-10-31 14:50:45Z

1

I had the same issue with Postgres. Try adding a SequenceGenerator to your id field:

@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;

Replace SEQ_EMPLOYEE with the name of the sequence in the database.

edited Oct 31, 2017 at 14:50

answered Oct 31, 2017 at 14:43

Wesley De Keirsmaeker

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3 Comments

faster_fene Over a year ago

No difference in error. Got same error such as : <pre> ERROR [2017-10-31 14:47:14,721] org.hibernate.AssertionFailure: HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): org.hibernate.AssertionFailure: null id in com.example.helloworld.entities.Employee entry (don't flush the Session after an exception occurs) </pre>

Wesley De Keirsmaeker Over a year ago

I forgot to change also the GeneratedValue. I have edited my post.

faster_fene Over a year ago

Thanks, @Wesley that worked! It started generating ID from 10 which I do not understand why also I have few questions on it as follows: 1) Is SEQ type generation not going to create any problem with respect uniqueness? 2) Any limitation on a number of ids can be generated? 3) Why 'Identity Generation' did not work in my case? It works in a single table with no foreign reference.

faster_fene · Accepted Answer · 2017-10-31 18:02:05Z

0

This is what worked for me :

@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)

answered Oct 31, 2017 at 18:02

faster_fene

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