I'm starting with Hibernate and I have an error that I just can't figure out.
I have the following Classes:
@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class AbstractColumn {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private String id;
private String name;
//Other stuff
}
Then I have
@Entity
public class DoubleColumn extends AbstractColumn implements Column {
@ElementCollection
private Map<Double,String> isNA;
private double min=0;
private double max=0;
@ElementCollection
private List<Double> data;
// a lot of stuff
}
And finally:
@Entity
public class DataFrame {
@OneToMany(cascade = CascadeType.ALL)
@PrimaryKeyJoinColumn
private List<AbstractColumn> data;
private String name;
@Id
@GeneratedValue
private String id;
@ElementCollection
private Map<String,Integer> colIndex;
//more stuff
}
The error I'm getting is:
Exception in thread "main" org.hibernate.id.IdentifierGenerationException: Unknown integral data type for ids : java.lang.String
at org.hibernate.id.IdentifierGeneratorHelper.getIntegralDataTypeHolder(IdentifierGeneratorHelper.java:224)
at org.hibernate.id.enhanced.SequenceStructure$1.getNextValue(SequenceStructure.java:98)
at org.hibernate.id.enhanced.NoopOptimizer.generate(NoopOptimizer.java:40)
at org.hibernate.id.enhanced.SequenceStyleGenerator.generate(SequenceStyleGenerator.java:432)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:105)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:675)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:667)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:662)
at Main.main(Main.java:285)
The only hint that the error throws is that the error is in the main class here:
DoubleColumn c1 = new DoubleColumn("Datos varios");
c1.addData(12);
c1.addData(11);
c1.addData(131);
c1.addData(121);
c1.addData(151);
c1.addData(116);
DataFrame datosHibernate = new DataFrame("Dataframe Hibernate");
datosHibernate.addColumn(c1);
Configuration hibernateConfig = new Configuration();
SessionFactory sessionFactory = hibernateConfig.configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(datosHibernate);
session.getTransaction().commit();
session.disconnect();
session.close();
System.exit(0);
The ids are Strings, and I have them annotated as @GeneratedValue (I think I do not need to initialize them myself). The relation @OneToMany have the cascade annotation so it should be mapped correctly.
I've tried the code WITHOUT the session.save line and doesn't throw errors, so is not a problem in the code per se, it has to be something with Hibernate.
My configuration file is:
<hibernate-configuration>
<session-factory>
<property name="connection.url">jdbc:h2:E:/bd;DB_CLOSE_DELAY=-1;MVCC=TRUE</property>
<property name="connection.driver_class">org.h2.Driver</property>
<property name="connection.username">user</property>
<property name="connection.password"></property>
<property name="dialect">org.hibernate.dialect.H2Dialect</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">create</property>
<mapping class="com.dataframe.estructuras.DataFrame"></mapping>
<mapping class="com.dataframe.estructuras.column.AbstractColumn"/>
<mapping class="com.dataframe.estructuras.column.types.DoubleColumn"/>
</session-factory>
</hibernate-configuration>
It creates the database file and I see all the SQL code generated, tables and all. Is when it tries to store the info when the thing breaks.
If you want String to be database key you need to use UUID to automatically generate key. Something like this:
@Id @GeneratedValue(generator="system-uuid")
@GenericGenerator(name="system-uuid", strategy = "uuid")
private String myId;
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