Question

I have a table DEAL and a table DEAL_TYPE. I would like to map this code:

public class Deal {    DealType type; }  public enum DealType {    BASE('Base'), EXTRA('Extra'); } 

The problem is that the data already exist in the database. And I’m having a hard time mapping the classes to the database.

The database looks something like that:

   TABLE DEAL {       Long id;       Long typeId;    }     TABLE DEAL_TYPE {        Long id;        String text;    } 

I know I could use a simple @OneToMany relationship from deal to deal type, but I would prefer to use an enum. Is this possible?

I almost got it working by using a EnumType.ORDINAL type. But unfortunately, my IDs in my deal type table are not sequential, and do not start at 1.

Any suggestions?

Answer 1

Hibernate is kind of terrible at Enums. It’s a strange failing of an otherwise pretty good ORM. The ‘easiest’ way to get around it is to declare your Enum a custom hibernate type. Fortunately, Hibernate wrote an example implementation which you can crib verbatim into your app:

http://www.hibernate.org/265.html

They even include instructions on how to use it. This is the pattern I use whenever I end up with the need to persist enums.