CODEWITHSUNDEEP
javamysqlhibernate
Edgaras Karka
Edgaras Karka

Reputation: 7852

Hibernate OneToMany MySQLIntegrityConstraintViolationException: Duplicate entry

I have two java hibernate entities:

@Entity
public class Match_soccer extends Match{
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int mid;

    ...

And other one: 

@Entity
public class Algo {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @OneToMany
    private List<Match_soccer> matches = new ArrayList<Match_soccer>();

    ...

And if I try save two different Algo entities but with some matches list I get Duplicate entry '6028' for key 'UK_auyvi1qkpdtaqrpuyv9je5rda' exception.

Hibernate create in database 3 tables: Algo Match_soccer and Table: 

Algo_Match_soccer
with columns:
Algo1_id    int(11)
matches_mid int(11) PK

My goal is to assign list of matches to Algo. Matches can be some in 2 different Algo objects.

Algo a1 = new Algo();
Algo a2 = new Algo();
SoccerDAO sd = new SoccerDAO();
List<Match_soccer> ms = sd.getMatches(DateFrom,DateTo); // Matches from database
a1.setMatches(ms);
a2.setMatches(ms);

I use this function to insert:

public void insertAlgo(Algo1 a){

    try {           
        session.beginTransaction();
        session.save(a);
        session.getTransaction().commit();
    }
    catch (RuntimeException e) {
        session.getTransaction().rollback();
        session.clear();
        throw e;
}

Upvotes: 2

Views: 267

Answers (2)

Guillermo
Guillermo

Reputation: 1533

Due to Match_soccer could have relationships with many Algo entities instance, the matches association/collection must be`@ManyToMany.

If you leave the association as @OneToMany it will define the UK//PK constraint for match_id that doesn't allows you to set same matches to two different Algo instances

Upvotes: 1

JB Nizet
JB Nizet

Reputation: 692131

Matches can be some in 2 different Algo objects

Then you don't have a OneToMany association, but a ManyToMany association. since an Algo has several matches, and a match belongs to several algos.

Change your mapping, and change the database schema accordingly: the PK of the join table should be the pair of IDs, and not just the match ID.

Upvotes: 1

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