Hibernate:"字段'id'没有默认值"

Question

我正面临着我认为Hibernate的一个简单问题,但无法解决它(Hibernate论坛无法访问肯定没有帮助).

我有一个简单的课程,我想坚持,但继续得到:

SEVERE: Field 'id' doesn't have a default value
Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not insert: [hibtest.model.Mensagem]
    at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
    [ a bunch more ]
Caused by: java.sql.SQLException: Field 'id' doesn't have a default value
    [ a bunch more ]

持久化类的相关代码是:

package hibtest.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Mensagem  {
    protected Long id;

    protected Mensagem() { }

    @Id
    @GeneratedValue
    public Long getId() {
        return id;
}

    public Mensagem setId(Long id) {
        this.id = id;
        return this;
    }
}

实际运行的代码很简单:

SessionFactory factory = new AnnotationConfiguration()
    .configure()
    .buildSessionFactory();

{
    Session session = factory.openSession();
    Transaction tx = session.beginTransaction();

    Mensagem msg = new Mensagem("YARR!");

    session.save(msg);

    tx.commit();
    session.close();
}

我在GeneratedValue注释中尝试了一些"策略",但它似乎没有用.初始化id也没有帮助!(例如Long id = 20L).

谁能解开一些光明？

编辑2:确认:搞乱@GeneratedValue(strategy = GenerationType.XXX)不解决它

已解决:重新创建数据库解决了问题

Answer 1

有时,即使在执行之后,对模型或ORM所做的更改也可能无法准确反映在数据库上SchemaUpdate.

如果错误实际上似乎缺乏合理的解释,请尝试重新创建数据库(或者至少创建一个新的数据库)并使用脚手架SchemaExport.

Answer 2

如果您希望MySQL自动生成主键,则必须在创建表时告诉它.您不必在Oracle中执行此操作.

在您必须包含的主键上AUTO_INCREMENT.请参阅下面的示例.

CREATE TABLE `supplier`  
(  
  `ID` int(11) NOT NULL **AUTO_INCREMENT**,  
  `FIRSTNAME` varchar(60) NOT NULL,  
  `SECONDNAME` varchar(100) NOT NULL,  
  `PROPERTYNUM` varchar(50) DEFAULT NULL,  
  `STREETNAME` varchar(50) DEFAULT NULL,  
  `CITY` varchar(50) DEFAULT NULL,  
  `COUNTY` varchar(50) DEFAULT NULL,  
  `COUNTRY` varchar(50) DEFAULT NULL,  
  `POSTCODE` varchar(50) DEFAULT NULL,  
  `HomePHONENUM` bigint(20) DEFAULT NULL,  
  `WorkPHONENUM` bigint(20) DEFAULT NULL,  
  `MobilePHONENUM` bigint(20) DEFAULT NULL,  
  `EMAIL` varchar(100) DEFAULT NULL,  
  PRIMARY KEY (`ID`)  
) 

ENGINE=InnoDB DEFAULT CHARSET=latin1;  

这是实体

package com.keyes.jpa;  

import java.io.Serializable;
import javax.persistence.*;
import java.math.BigInteger;

/**
 * The persistent class for the parkingsupplier database table.
 * 
 */
@Entity
@Table(name = "supplier")
public class supplier implements Serializable
{
  private static final long serialVersionUID = 1L;

  @Id
  **@GeneratedValue(strategy = GenerationType.IDENTITY)**
  @Column(name = "ID")
  private long id;

  @Column(name = "CITY")
  private String city;

  @Column(name = "COUNTRY")
  private String country;

  @Column(name = "COUNTY")
  private String county;

  @Column(name = "EMAIL")
  private String email;

  @Column(name = "FIRSTNAME")
  private String firstname;

  @Column(name = "HomePHONENUM")
  private BigInteger homePHONENUM;

  @Column(name = "MobilePHONENUM")
  private BigInteger mobilePHONENUM;

  @Column(name = "POSTCODE")
  private String postcode;

  @Column(name = "PROPERTYNUM")
  private String propertynum;

  @Column(name = "SECONDNAME")
  private String secondname;

  @Column(name = "STREETNAME")
  private String streetname;

  @Column(name = "WorkPHONENUM")
  private BigInteger workPHONENUM;

  public supplier()
  {
  }

  public long getId()
  {
    return this.id;
  }

  public void setId(long id)
  {
    this.id = id;
  }

  public String getCity()
  {
    return this.city;
  }

  public void setCity(String city)
  {
    this.city = city;
  }

  public String getCountry()
  {
    return this.country;
  }

  public void setCountry(String country)
  {
    this.country = country;
  }

  public String getCounty()
  {
    return this.county;
  }

  public void setCounty(String county)
  {
    this.county = county;
  }

  public String getEmail()
  {
    return this.email;
  }

  public void setEmail(String email)
  {
    this.email = email;
  }

  public String getFirstname()
  {
    return this.firstname;
  }

  public void setFirstname(String firstname)
  {
    this.firstname = firstname;
  }

  public BigInteger getHomePHONENUM()
  {
    return this.homePHONENUM;
  }

  public void setHomePHONENUM(BigInteger homePHONENUM)
  {
    this.homePHONENUM = homePHONENUM;
  }

  public BigInteger getMobilePHONENUM()
  {
    return this.mobilePHONENUM;
  }

  public void setMobilePHONENUM(BigInteger mobilePHONENUM)
  {
    this.mobilePHONENUM = mobilePHONENUM;
  }

  public String getPostcode()
  {
    return this.postcode;
  }

  public void setPostcode(String postcode)
  {
    this.postcode = postcode;
  }

  public String getPropertynum()
  {
    return this.propertynum;
  }

  public void setPropertynum(String propertynum)
  {
    this.propertynum = propertynum;
  }

  public String getSecondname()
  {
    return this.secondname;
  }

  public void setSecondname(String secondname)
  {
    this.secondname = secondname;
  }

  public String getStreetname()
  {
    return this.streetname;
  }

  public void setStreetname(String streetname)
  {
    this.streetname = streetname;
  }

  public BigInteger getWorkPHONENUM()
  {
    return this.workPHONENUM;
  }

  public void setWorkPHONENUM(BigInteger workPHONENUM)
  {
    this.workPHONENUM = workPHONENUM;
  }

}

Answer 3

您必须在hbm2ddl属性中使用update.进行更改并将其更新为Create,以便它可以创建表.

<property name="hbm2ddl.auto">create</property>

它对我有用.

Answer 4

看一下GeneratedValue这个策略吧.它通常看起来像:

@GeneratedValue(strategy=GenerationType.IDENTITY)

Answer 5

手动从数据库中删除表，然后重新运行应用程序对我有用。在我的情况下，我猜表没有正确创建（有约束）。

Answer 6

我有这个问题。我的错误是我将可插入和可更新的文件设置为 false 并试图在请求中设置该字段。该字段在 DB 中设置为 NON NULL。

@ManyToOne
@JoinColumn(name="roles_id",  referencedColumnName = "id", insertable = false, updatable = false, nullable=false)
@JsonBackReference
private Role role;

后来我改成 - insertable = true, updatable = true

@ManyToOne
@JoinColumn(name="roles_id",  referencedColumnName = "id", insertable = true, updatable = true, nullable=false)
@JsonBackReference
//@JsonIgnore
private Role role;

后来它完美地工作了。

Answer 7

我来到这里是因为错误消息，结果我有两个同名的表。

Answer 8

我有同样的问题。我找到了教程《使用外键注释的 Hibernate 一对一映射示例》，并按如下步骤操作：

使用以下脚本创建数据库表：

create table ADDRESS (
   id INT(11) NOT NULL AUTO_INCREMENT,
   street VARCHAR(250) NOT NULL,
   city  VARCHAR(100) NOT NULL,
   country  VARCHAR(100) NOT NULL,
   PRIMARY KEY (id)
);

create table STUDENT (
    id            INT(11) NOT NULL AUTO_INCREMENT, 
    name          VARCHAR(100) NOT NULL, 
    entering_date DATE NOT NULL, 
    nationality   TEXT NOT NULL, 
    code          VARCHAR(30) NOT NULL,
    address_id INT(11) NOT NULL,
    PRIMARY KEY (id),
    CONSTRAINT student_address FOREIGN KEY (address_id) REFERENCES ADDRESS (id)   
);

这是上面表格中的实体

@Entity
@Table(name = "STUDENT")
public class Student implements Serializable {

    private static final long serialVersionUID = 6832006422622219737L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;

 }

@Entity
@Table(name = "ADDRESS")
public class Address {

    @Id @GeneratedValue
    @Column(name = "ID")
    private long id;
}

问题解决了。

注意：主键必须设置为AUTO_INCRMENT