Hibernate Unknown integral data type for ids

Question

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 isNA; private double min=0; private double max=0; @ElementCollection private List data; // a lot of stuff } ``` And finally: ``` @Entity public class DataFrame { @OneToMany(cascade = CascadeType.ALL) @PrimaryKeyJoinColumn private List data; private String name; @Id @GeneratedValue private String id; @ElementCollection private Map colIndex; //more stuff } ``` The error I'm getting is: ``` Exception in thread "main" org.hibernate.id.IdentifierGenerationException: Unknown integral data type…

Accepted Answer

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;
```

UPDATE

The way of doing has evolved to the following usage

```
import org.hibernate.annotations.UuidGenerator;
// other code 
@Id
@UuidGenerator
public String id;
```

Hibernate Unknown integral data type for ids

Solution

Problem