Storing EnumSet in a database?

Question

So in C++/C# you can create flags enums to hold multiple values, and storing a single meaningful integer in the database is, of course, trivial.

In Java you have Enu

Answer 1

Without going into the debate about pros and cons of ordinal values in the database - I posted a possible answer to the given question here: JPA map collection of Enums

The idea is to create a new PersistentEnumSet which uses the implementation of java.util.RegularEnumSet, but offers the elements bitmask to JPA.

That one can than be used in an embeddable:

@Embeddable
public class InterestsSet extends PersistentEnumSet {
  public InterestsSet() {
    super(InterestsEnum.class);
  }
}

And that set is used in the entity:

@Entity
public class MyEntity {
  // ...
  @Embedded
  private InterestsSet interests = new InterestsSet();
}

For further comments see my answer over there.