Jpa 如果外键约束失败，则无法删除或更新父行

无法删除或更新父行：外键约束失败（

gopick

orders\u paid\u items

，约束

fkeeeefhbl6j5xhs7nnt5mn530f8

外键（

paid\u product\u id

，

paid\u items\u user\u id

）引用

cart

（

product id

，

用户id>）

购物车实体如下

    @Entity
    @ToString
    @EqualsAndHashCode
    @IdClass(CartIdPk.class)
    public class Cart implements Serializable {

    @Column(unique = true)
    private Long id = Long.parseLong(String.format("%06d", new Random().nextInt(999999)));

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

    private CartStatus cartStatus = CartStatus.IN_CART;

    @Id
    private int productId;

    private int quantity = 0;

    @Column(length = 10, nullable = true)
    private String discount;

    @Column(length = 30, nullable = true)
    private String paymentRef;

    @JsonIgnore
    @Column(insertable = false, updatable = true)
    @UpdateTimestamp
    private Timestamp lastModified;

    @CreationTimestamp
    private Timestamp dateCreated;

}


    @lombok.Data
    @Entity
    public class Orders implements Serializable {

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

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

    @OneToMany(fetch = FetchType.LAZY)
    private Collection<Cart> paidItems;

    @JsonIgnore
    @Column(insertable = false, updatable = true)
    @UpdateTimestamp
    private Timestamp lastModified;

    @CreationTimestamp
    private Timestamp dateCreated;

}

Id类对象CartIdPk

@NoArgsConstructor
@AllArgsConstructor
@lombok.Data
public class CartIdPk implements Serializable {

    private Long user;

    private int productId;
}


订单实体如下

    @Entity
    @ToString
    @EqualsAndHashCode
    @IdClass(CartIdPk.class)
    public class Cart implements Serializable {

    @Column(unique = true)
    private Long id = Long.parseLong(String.format("%06d", new Random().nextInt(999999)));

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

    private CartStatus cartStatus = CartStatus.IN_CART;

    @Id
    private int productId;

    private int quantity = 0;

    @Column(length = 10, nullable = true)
    private String discount;

    @Column(length = 30, nullable = true)
    private String paymentRef;

    @JsonIgnore
    @Column(insertable = false, updatable = true)
    @UpdateTimestamp
    private Timestamp lastModified;

    @CreationTimestamp
    private Timestamp dateCreated;

}


    @lombok.Data
    @Entity
    public class Orders implements Serializable {

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

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

    @OneToMany(fetch = FetchType.LAZY)
    private Collection<Cart> paidItems;

    @JsonIgnore
    @Column(insertable = false, updatable = true)
    @UpdateTimestamp
    private Timestamp lastModified;

    @CreationTimestamp
    private Timestamp dateCreated;

}

在java中使用JPA和ORMs的经验法则是记住，您同时拥有一个对象模型和一个关系数据库模型，并且必须在这两个模型中进行更改

因此，订单和购物车之间存在1对多的差异

因此，为了便于讨论，您尝试删除当前在订单中的购物车。当保存发生时，您将得到一个完整性冲突，因为您试图删除的购物车仍然被订单引用

您需要做的是在删除之前从卡中删除订单，因为您在订单中引用了购物车

始终尝试在“对象”级别和数据库级别进行更改。
因此，我所做的只是从productId中删除id注释，并删除嵌入的id类，因此在插入之前，我会根据我的用例进行手动集成检查，效果良好