休眠字段“ user_id”没有默认值

Question

当我在具有以下三个实体的休眠项目中工作时，当我在实体之间添加一个原子关系时，字段“ user_id”没有默认值。

当尝试插入新主题时，我得到

休眠状态：插入主题（内容，日期，图像，图像名称）值（？，？，？，？）2016年5月8日11:46:56 PM org.hibernate.util.JDBCExceptionReporter logExceptions警告：SQL错误：1364，SQLState ：HY000 2016年5月8日，下午11:46:56 org.hibernate.util.JDBCExceptionReporter logExceptions严重：字段'user_id'没有默认值

并尝试插入新的类似记录时得到相同的错误

用户类别

public class User implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "user_id", unique = true, nullable = false)
private long id;

@Column(name = "first_name",  nullable = false, length = 10)
private String firstName;

@Column(name = "last_name",  nullable = false, length = 10)
private String lastName;

@Column(name = "role",  nullable = false, length = 10)
private String role;


@Column(name = "email", unique = true, nullable = false, length = 10)
private String email;


@Column(name = "password", nullable = false, length = 10)
private String password;

@OneToMany(fetch = FetchType.LAZY, mappedBy = "user")
private Set<Topics> topics=new HashSet<Topics>();

@OneToMany(fetch = FetchType.LAZY, mappedBy = "user1")
private Set<Like> likes=new HashSet<Like>();

//getter and setter

喜欢上课

@Entity
@Table(name = "likes")
 public class Like implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "likes_id", unique = true, nullable = false)
private long id;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", nullable = false,insertable = false, updatable = false)
private User user1;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "topics_id", nullable = false,insertable = false,   updatable = false)
private Topics topics;
 //getter and setter

主题课

 @Entity
 @Table(name = "topics")
 public class Topics implements Serializable{

/**
 * 
 */
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "topics_id", unique = true, nullable = false)
private long id;

@Column(name = "content", unique = true, nullable = false)
private String content;

@Temporal(TemporalType.DATE)
@Column(name = "date")
private Date date;

@Column(name = "image_name")
private String imageName;

@Lob
@Column(name="image", columnDefinition="longblob")
private byte[] image;


@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", nullable = false,insertable = false, updatable = false)
private User user;

@OneToMany(fetch = FetchType.LAZY, mappedBy = "topics")
private Set<Like> likes=new HashSet<Like>();
 //getter and setter

休眠配置文件

 <hibernate-configuration>
<session-factory>
    <property name="hibernate.bytecode.use_reflection_optimizer">false</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.password">root</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/social</property>
    <property name="hibernate.connection.username">root</property>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="show_sql">true</property>
    <property name="hbm2ddl.auto">create</property>
    <mapping class="com.pro.model.User"></mapping>
    <mapping class="com.pro.model.Topics"></mapping>
    <mapping class="com.pro.model.Like"></mapping>
</session-factory>

Answer 1

可能您没有设置试图插入主题表的主题用户。

还有一件事，使用单数的类名。 主题->主题

Answer 2

我在这里看到许多问题：

• 您确定主题在所有方面都不是ManyToMany而不是OneToMany（似乎是无效的东西）...（一个人可能对许多主题感兴趣，主题可以包含许多人）
• 如果您想与新用户继续使用新主题，并且您应该使用@OneToMany（ 层叠 = {CascadeType.PERSIST，CascadeType.MERGE}）如果您在字段中正确设置，则应该可以使用，否则，您可能会遭受循环引用...
• 我宁愿使用GenerationType.SEQUENCE ，因为AUTO就像一个黑盒子。 您不会确切知道发生了什么...（例如，oracle将创建一个序列以提供唯一的主键）