CODEWITHSUNDEEP
hibernatespring-data-jpacascading-deletes
neC
neC

Reputation: 1

Removing Child from unidirectional relation in Hibernate/JPA

I have two entities User and Expense connected by a unidirectional @ManyToMany relation. While trying to delete a User a Referential integrity constraint violation is thrown. What I want to happen if a User gets deleted:

I know why this happens and what the problem is however even with looking at other StackOverflow articles I have not found one that can solve my problem. Because the User does not have a @ManyToMany field for Expenses, all solutions I found, do not work.

Thanks in advance!

(I removed all Lombok Getters, Setters for readablity)

My entities are:

public class Expense {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotNull
    private double amount;

    @NotNull
    private String name;


    @NotNull
    @OneToOne(fetch = FetchType.EAGER)
    private User spentBy;

    @OnDelete(action = OnDeleteAction.CASCADE)
    @LazyCollection(LazyCollectionOption.FALSE)
    @ManyToMany
    private List<User> spentFor;

public class User implements UserDetails {
    @SequenceGenerator(
        name = "user_sequence",
        sequenceName = "user_sequence",
        allocationSize = 1
    )
    @Id
    @GeneratedValue(
        strategy = GenerationType.SEQUENCE,
        generator = "user_sequence")
    @Column(name = "id", nullable = false)
    private Long id;


    ... (no relation to Expense entity!)

detailed Stacktrace (german version, but you might understand what you need to):

Caused by: org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: Referentielle Integrität verletzt: "FKLECP8QCGQCV5JQGM8FTNMIY0Q: PUBLIC.EXPENSE_SPENT_FOR FOREIGN KEY(SPENT_FOR_ID) REFERENCES PUBLIC.APPLICATION_USER(ID) (CAST(2 AS BIGINT))"
Referential integrity constraint violation: "FKLECP8QCGQCV5JQGM8FTNMIY0Q: PUBLIC.EXPENSE_SPENT_FOR FOREIGN KEY(SPENT_FOR_ID) REFERENCES PUBLIC.APPLICATION_USER(ID) (CAST(2 AS BIGINT))"; SQL statement:
delete from application_user where id=? [23503-214]

I have already tried using the @OnDelete Annotation but this did not change anything. Also the cascade = CascadeType.ALL is not suitable, as I have the case where the child gets deleted and not the parent.

Upvotes: 0

Views: 216

Answers (1)

sachin
sachin

Reputation: 11

In bidirectional mapping, one entity will be unaware of another entity

so in a bidirectional relationship, we mention which entity side will update links between the two tables.

To save/delete the association, save the owner entity of the relation.

Upvotes: 1

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