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java - 如何避免使用 JPA 在实体关系中违反外键约束

问题描述

@Entity
@Table(name = "PERSISTENCE_USER")

    public class User implements Serializable {
        // HERE IS A SNIPPET
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
    
        private Long id;
        @NotNull
        private String firstName;
        @NotNull
        private String lastName;
        ................
    }
@Entity
@Table(name = "PERSISTENCE_ORDER")
@NamedQueries({
    @NamedQuery(
            name = "findAllorders",
            query = "SELECT o FROM CustomerOrder o"
    ),
    @NamedQuery(
            name = "deleteAll",
            query = "DELETE FROM CustomerOrder"
    )
})

    public class CustomerOrder implements Serializable {
    
        //HERE IS A SNIPPET
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        private Long id;
        @NotNull
        String status;
        @NotNull
        @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
        private List<LineItem> lineItems;
        @NotNull
        @ManyToOne
        private User customer;
        ...........
    }

当我尝试使用 User 实体删除具有单向 @ManyToOne 的 CustomerOrder 实体时，我收到以下错误：

Internal Exception: org.apache.derby.shared.common.error.DerbySQLIntegrityConstraintViolationException: DELETE on table 'PERSISTENCE_ORDER' caused a violation of foreign key constraint 'PRSSTNCSRPRSSRDRSD' for key (21).  The statement has been rolled back.
Error Code: 20000
Call: DELETE FROM PERSISTENCE_ORDER
Query: DeleteAllQuery(name="deleteAll" referenceClass=CustomerOrder sql="DELETE FROM PERSISTENCE_ORDER")
    at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:331)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeDirectNoSelect(DatabaseAccessor.java:905)
    at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeNoSelect(DatabaseAccessor.java:967)
        ............................................................................
        ............................................................................
Caused by: org.apache.derby.shared.common.error.DerbySQLIntegrityConstraintViolationException: DELETE on table 'PERSISTENCE_ORDER' caused a violation of foreign key constraint 'PRSSTNCSRPRSSRDRSD' for key (21).  The statement has been rolled back.

之后，我尝试在删除 CustomerOrder 实体之前先删除 User 实体，但这没有任何区别。我应该如何定义实体关系映射以避免此错误？

谢谢

PS：我正在使用 Glassfish 5.1，EclipseLink 在 Windows 10 64 位和 Apache Derby DB 上运行

标签： javajdbceclipselinkjpa-2.1java-ee-8

解决方案

当发出“DELETE FROM CustomerOrder”批量删除查询时，JPA 不会为您做任何事情 - 它会完全按照 JPQL 的要求发出 SQL - 因此您可以通过清空或删除对行的任何引用来维护你想删除，在你删除它们之前。

异常本身表明违反了 FK 约束“PRSSTNCSRPRSSRDRSD”，可以在数据库中找到它以准确告诉您是哪个关系导致了问题。查看 CustomerOrder 实体，lineItems 集合的映射方式是将外键放入 LineItems 表中，这需要在删除成功之前清理这些行。

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