CODEWITHSUNDEEP
javahibernate
Paul Taylor
Paul Taylor

Reputation: 13110

Why has Hibernate created join table that prevents me emptying contents of table

I have three Hibernate Entities:

Song represent a song file (e.g mp3 file), CoverArt contains songs coverart, a song can have multiple pieces of coverart

Within Song I define link to CoverArt as:

@OneToMany(fetch=FetchType.LAZY, cascade={CascadeType.ALL})
@JoinColumn(name = "recNo")
private List<CoverArt> coverArts;

Within CoverArt there is no link defined to Song, we just have

@Id
@GeneratedValue
private Integer id;

The application works okay, except when I want to empty the Song and CoverArt entities.

It doesn't happen consistently but if I try and delete from Song first

e.g 
            String hql = String.format("delete from CoverArt");
            Query query = session.createQuery(hql);
            query.executeUpdate();

            hql = String.format("delete from Song");
            query = session.createQuery(hql);
            query.executeUpdate();

            session.getTransaction().commit();

I get exception:

Caused by: org.h2.jdbc.JdbcSQLException: Referential integrity constraint violation: "FK_CBUK1UQ1D0DQAA077XH16SRX2: PUBLIC.SONG_COVERART FOREIGN KEY(COVERARTS_ID) REFERENCES PUBLIC.COVERART(ID) (13)"; SQL statement:

and if I try the other way 

String hql = String.format("delete from Song");
            Query query = session.createQuery(hql);
            query.executeUpdate();

            hql = String.format("delete from CoverArt");
            query = session.createQuery(hql);
            query.executeUpdate();

I get exception

Caused by: org.h2.jdbc.JdbcSQLException: Referential integrity constraint violation: "FK_4B4O39V3RSF1IWWRIX6QQQTLK: PUBLIC.SONG_COVERART FOREIGN KEY(SONG_RECNO) REFERENCES PUBLIC.SONG(RECNO) (1)"; SQL statement:

So its impossible to empty the tables, CoverArt entity only exists as part of a Song so I assumed their would only be a Foreign Key from a COVER_ART table to SONG table and expected I could delete everything from CoverArt without a problem, but there is an interim table created SONG_COVERART that has foreign keys to both tables preventing deletion.

What am I doing wrong (using Hibernate 4.3.11)

Upvotes: 0

Views: 72

Answers (1)

JB Nizet
JB Nizet

Reputation: 691755

Probably because in a previous version of your code didn't have the JoinColumn annotation, and Hibernate thus created a join table for this association, that you filled, but forgot to delete.

Upvotes: 1

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