Hibernate复合主键外键重叠保存时bank_id非空约束报错如何解决

你触发异常的核心原因是BonusEntity的关联注解配置错误：

• 你给关联AccountEntity的三个@JoinColumn全部设置了insertable = false, updatable = false，意味着Hibernate在插入数据时不会处理这三个外键字段的写入
• 其中cluster_id属于BonusEntity的复合主键，所以插入时会自动赋值，但bank_id、user_id没有任何对应字段负责写入，自然就是NULL，触发数据库非空约束

你只需要调整关联注解的配置，仅保留主键重叠字段cluster_id的insertable = false, updatable = false配置，剩下两个外键字段放开写入权限即可，Hibernate会自动从关联的AccountEntity主键中提取对应值写入表中：

调整后的BonusEntity代码示例：

@Entity
@Table(name = "cbonus")
public class BonusEntity {
    @EmbeddedId
    @AttributeOverride(name = "id", column = @Column(name = "id"))
    @AttributeOverride(name = "clusterId", column = @Column(name = "cluster_id"))
    private BonusId bonusId;
    private boolean released;
    
    @ManyToOne(targetEntity = AccountEntity.class, optional = false, fetch = FetchType.LAZY)
    @JoinColumn(name = "cluster_id", referencedColumnName = "cluster_id", insertable = false, updatable = false)
    // 去掉bank_id、user_id对应的insertable、updatable禁用配置
    @JoinColumn(name = "bank_id", referencedColumnName = "bank_id")
    @JoinColumn(name = "user_id", referencedColumnName = "user_id")
    private AccountEntity account;
}

如果你的业务场景需要单独访问bank_id、user_id字段不需要加载整个AccountEntity，也可以在BonusEntity中显式定义这两个字段，再调整关联注解的配置关联到这两个字段即可：

@Entity
@Table(name = "cbonus")
public class BonusEntity {
    @EmbeddedId
    @AttributeOverride(name = "id", column = @Column(name = "id"))
    @AttributeOverride(name = "clusterId", column = @Column(name = "cluster_id"))
    private BonusId bonusId;
    
    @Column(name = "bank_id", nullable = false)
    private Long bankId;
    @Column(name = "user_id", nullable = false)
    private String userId;
    
    private boolean released;
    
    @ManyToOne(targetEntity = AccountEntity.class, optional = false, fetch = FetchType.LAZY)
    @JoinColumn(name = "cluster_id", referencedColumnName = "cluster_id", insertable = false, updatable = false)
    @JoinColumn(name = "bank_id", referencedColumnName = "bank_id", insertable = false, updatable = false)
    @JoinColumn(name = "user_id", referencedColumnName = "user_id", insertable = false, updatable = false)
    private AccountEntity account;
    
    // 自定义setAccount方法自动同步bankId、userId字段
    public void setAccount(AccountEntity account) {
        this.account = account;
        this.bankId = account.getAccountId().getBankId();
        this.userId = account.getAccountId().getUserId();
    }
}

使用这种方案时，保存BonusEntity前调用setAccount方法即可自动完成字段同步，不需要手动赋值两个外键字段。

内容的提问来源于stack exchange，提问作者Vasiliy Tungusov