Hibernate with strange behavior

[Marcus Laranjeira]

In some tests with Hibernate, to remove an entity that appears in 3 lines of an intermediate table, instead of removing it to 3 lines in this entity, he removed and inserted again ALL lines referring to those who remained in the intermediate table.

To understand better, see the code:

Entity TEAM:

// imports here... 
@Entity
public class Team {

	@Id private int team;

	private String name;

	@OneToOne
	private TeamType teamType;

	@ManyToMany
	private List<individual> individuals = new ArrayList<individual>();
	
	// getters & setters here...
}

Entity TEAMTYPE:

// imports here...
@Entity
public class TeamType {
	
	@Id
	private int teamType;

	private String teamTypeName;

	// getters & setters here...
}

Entity INDIVIDUAL:

// imports here... 

@Entity
public class Individual {

	@Id
	private int id;
	private String name;

	@ManyToMany(mappedBy = "individuals")
	private List<Team> teams;

	// getters & setters here...
}

Hibernate generated the following SQL script:

drop table Team cascade constraints
drop table Team_Individual cascade constraints
drop table Individual cascade constraints
drop table TeamType cascade constraints

create table Team (
	team number(10,0) not null,
	name varchar2(255 char),
	teamType_teamType number(10,0),
	primary key (team) )

create table Team_Individual (
	teams_team number(10,0) not null,
	individuals_id number(10,0) not null )

create table Individual (
	id number(10,0) not null,
	name varchar2(255 char),
	primary key (id) )

create table TeamType (
	teamType number(10,0) not null,
	nameTeamType varchar2(255 char),
	primary key (teamType) )

alter table Team
	add constraint FK7C2D8A55ACA0E820
	foreign key (teamType_teamType) references TeamType

alter table Team_Individual
	add constraint FKF6E014F11DC9DE83
	foreign key (teams_team) references Team

alter table Team_Individual
	add constraint FKF6E014F167BB8FCD
	foreign key (individuals_id) references Individual

The database was empty, so TeamTypes, Teams and individuals were added:

//...
t1.setTeamTypeName("Test TeamType1");
t1.setTeamType(1);
//t2...

//...
e1.setTeam(1);
e1.setName("Test Team 1");
e1.setTeamType(t1);
//e2, e3...

//...
p1.setName("Test I1");
p1.setId(1);
//p2, p3, p4, p5, p6, p7...

//...

In order to obtain such a situation that attend this diagram:



Then, the intermediate table was something like this:

TEAMS_TEAM     INDIVIDUALS_ID
       1            1
       1            2
       1            3
       1            7
       2            3
       2            4
       2            5
       2            7
       3            1
       3            5
       3            6
       3            7

The problem I found is to remove the individual P7 with ID 7. Here he is on 3 teams, and correctly displayed on 3 lines of intermediate table with the correct relationship with the 3 teams.

The code to remove it is this:

//...
Dao<Individual> IndividualDao = new Dao<Individual>(session, Individual.class);
Individual p7 = IndividualDao.load(7);
Transaction tx = session.beginTransaction();

//Take out the individual of the teams to remove 

p.getTeams().get(0).getIndividuals().remove(p7);
p.getTeams().get(1).getIndividuals().remove(p7);
p.getTeams().get(2).getIndividuals().remove(p7);

// try catch...
IndividualDao.delete(p7);
tx.commit();
//...

In implementing this, Hibernate should do everything I need, besides deleting the row relating to the individual, it should only delete 3 lines in the intermediate table. Except that instead he:

Hibernate:
	delete
	from
		Team_Individual
	where
		teams_team=?
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	delete
	from
		Team_Individual
	where
		teams_team=?
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	delete
	from
		Team_Individual
	where
		teams_team=?
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	insert
	into
		Team_Individual
		(teams_team, individuals_id)
	values
		(?, ?)
Hibernate:
	delete
	from
		Team_Individual
	where
		teams_team=?

I have also implemented a trigger in the database (Oracle) and it inserted as well as deleted. I suspected that the INSERTS were informational only. It does delete individual correctly. But it's inserting again into the intermediate table. The most strange is that after this operation the intermediate table is correct and no exceptions are thrown.

I can't understand why Hibernate is doing this.

For a table with 12 records, this is "peanuts", but imagine if I had 2,000,000 and remove 3? it would reinsert 1,999,997?

Where am I missing?

Regards from Brazil!

[Rahul Babbar]

Marcus Laranjeira wrote:

p.getTeams().get(0).getIndividuals().remove(p7);
p.getTeams().get(1).getIndividuals().remove(p7);
p.getTeams().get(2).getIndividuals().remove(p7);

// try catch...
IndividualDao.delete(p7);
tx.commit();

not sure whether you need to remove the individual from all the teams....
I have not worked much on many to many mappings in hibernate, but i am wondering why a simple "session.remove(p7)" will not work.
Can you try it with "session.remove(P7)" and see if any exception comes...

To Brazil, with love...

[Marcus Laranjeira]

Hello Rahul,

Thanks for your reply!

I did it already! Look at the exceptions:

Hibernate: 
    select
        pessoa0_.id as id1_0_,
        pessoa0_.nome as nome1_0_ 
    from
        Pessoa pessoa0_ 
    where
        pessoa0_.id=?
Hibernate: 
    delete 
    from
        Pessoa 
    where
        id=?
12:00:16,547  WARN JDBCExceptionReporter:77 - SQL Error: 2292, SQLState: 23000
12:00:16,547 ERROR JDBCExceptionReporter:78 - ORA-02292: integrity restriction (TEST.FKF6E014F167BB8FCD) violated - child record found

12:00:16,547  WARN JDBCExceptionReporter:77 - SQL Error: 2292, SQLState: 23000
12:00:16,547 ERROR JDBCExceptionReporter:78 - ORA-02292: integrity restriction (TEST.FKF6E014F167BB8FCD) violated - child record found

12:00:16,563 ERROR AbstractFlushingEventListener:301 - Could not synchronize database state with session
[color=red]org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:146)
	at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
	at br.com.laranjeira.test.TestRemoveIndividual.main(TestRemoveIndividual.java:42)
Caused by: java.sql.BatchUpdateException: ORA-02292: integrity restriction (TEST.FKF6E014F167BB8FCD) violated - child record found

	at oracle.jdbc.driver.DatabaseError.throwBatchUpdateException(DatabaseError.java:867)
	at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(OraclePreparedStatement.java:14480)
	at oracle.jdbc.driver.OracleStatementWrapper.executeBatch(OracleStatementWrapper.java:589)
	at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1723)
	at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:246)[/color]
	... 8 more
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
	at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71)
	at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237)
	at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:146)
	at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298)
	at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
	at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
	at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
	at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106)
	at br.com.laranjeira.test.TesteRemoveIndividual.main(TestRemoveIndividual.java:42)
Caused by: java.sql.BatchUpdateException: ORA-02292: integrity restriction (TEST.FKF6E014F167BB8FCD) violated - child record found

	at oracle.jdbc.driver.DatabaseError.throwBatchUpdateException(DatabaseError.java:867)
	at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(OraclePreparedStatement.java:14480)
	at oracle.jdbc.driver.OracleStatementWrapper.executeBatch(OracleStatementWrapper.java:589)
	at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1723)
	at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
	at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:246)
	... 8 more

Thanks again!

[Rahul Babbar]

I think you can try to put the cascade="all" attribute for your association from Individual to the Team ...

[Marcus Laranjeira]

Rahul,



I tried again with your suggestion and it did not work. Remains exactly the same problem.

Tested the various CASCADE options and there was no change in behavior.

[Marcus Laranjeira]

Problem solved!

I used SET instead of LIST!

Look at here and here!!!

Now it works!

[Rahul Babbar]

Thanks for sharing the solution and the links...