How to combine manual insert and JPA Id generation?

Question

I am running in-container tests with arquillian. I am prepopulating the database by adding an import.sql to the deployment. During the test I would like to create some more entities.

Unfortunately, this fails with a PersistenceException:

javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: Unique index or primary key violation: "PRIMARY_KEY_BE ON PUBLIC.KVS_MIPO_DOWNLOAD(ID)"

If I do not prepopulate the DB, or do not persist new entities, everything runs smoothly.

The id is the only unique field, so I strongly suspect that it must be the id generation using a sequence.

@Entity
@Table(name = "KVS_MIPO_DOWNLOAD")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "type", discriminatorType = DiscriminatorType.STRING)
public abstract class DownloadResource implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    protected Integer id;

This entity is the superclass of another concrete entity, which does not add any unique attributes.

What can be done to be able to accomodate both possibilitiees - inserting manually and using a generated id?

Thank you

I am working with JPA 2 over Hibernate 4.0.1 in JBoss 7.1.1. The database is Sybase ASE 15.

EDIT: one workaround I have found so far is to set the Ids of the manually added entities high enough to avoid collisions. But this is not good enough for production - too many employees have write access to the db and may be tempted to add stuff manually. I would prefer the application to be robust enough not to die and explode in this case.

score 3 · Accepted Answer · answered Jan 18 '13 at 18:36

Use negative values for your manual ids. Hibernate shouldn't generate negative ones.

Optionally, use your own id generator that skips a particular range (or skips say numbers divisible by 7; some such scheme).

Sample ID generator:

import org.hibernate.HibernateException;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.IdentifierGenerator;

public class MyGenerator implements IdentifierGenerator {

    public Serializable generate(SessionImplementor session, Object object)
            throws HibernateException {
        return 1; // TODO: Your scheme to create an Integer;
    }
}

To use this annotate as follows:

@Id
@GeneratedValue(strategy = GenerationType.AUTO, generator = "myid")
@GenericGenerator(name = "myid", strategy = "com.x.y.z.MyDGenerator")
public int getId() {
    return _id;
}

Cool, I didn't know one could use negative numbers. Using a custom generator sounds reasonable too, I would either generate negative integers or count back from Integer.MAX_VALUE. Thank you, kabram — kostja, Jan 18 '13 at 18:50

score 1 · Answer 2 · answered Jan 18 '13 at 18:49

1

You could also use UUIDs as id or, alternatively, a sequence. Manually added data could refer to the sequence as well.

answered Jan 18 '13 at 18:49

sorencito

2,517
20
21

+1. I am using a vanilla hibernate-generated sequence now. It simply starts at 1 and increments by 1, so I guess I will implement a custom generator like kabram proposed. UUID sounds good too though, I'll look into it. Thank you sorencito – kostja Jan 18 '13 at 18:53
I was referring to a database sequence. This decouples the id generation from the application. – sorencito Jan 19 '13 at 11:05

Tobias Liefke · Answer 3 · 2014-12-23T23:35:53.030

1

If you use Fastnate you can create the import.sql with the correct IDs, sufficient for your JPA model and your database.

For example you could create your entities this way:

EntitySqlGenerator generator = new EntitySqlGenerator(new FileWriter("import.sql"));
List<DownloadResource> resources = createDownloadResources();
generator.write(resources);

There are some more options to create the import.sql, but for a start that should be enough.

Fastnate has currently no special support for Sybase, but for most things the default dialect (H2) will work as well.

edited Dec 23 '14 at 23:35

answered Dec 17 '14 at 20:34

Tobias Liefke

8,637
2
41
58

Sounds interesting. However simply dropping a tool name is only a good start ;) Could you add the relevant details of what and how to your answer, something minimally viable? – kostja Dec 18 '14 at 03:37
I hope the given example is enough. The topic is far to complex to describe all the options in a single answer. – Tobias Liefke Dec 23 '14 at 23:36

How to combine manual insert and JPA Id generation?

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