Hibernate/persistence without @Id
hibernate, hibernate-annotations, java, primary-key
Solution
If there's a combination of columns that makes a row unique, model a primary key class around the combination of columns. If there isn't, you're basically out of luck -- but you should reexamine the design of the view since it probably doesn't make sense.
There are a couple different approaches:
@Entity
public class RegionalArticle implements Serializable {
@Id
public RegionalArticlePk getPk() { ... }
}
@Embeddable
public class RegionalArticlePk implements Serializable { ... }
Or:
@Entity
public class RegionalArticle implements Serializable {
@EmbeddedId
public RegionalArticlePk getPk() { ... }
}
public class RegionalArticlePk implements Serializable { ... }
The details are here: https://docs.jboss.org/ejb3/app-server/HibernateAnnotations/reference/en/html_single/index.html#d0e1517
Here's a posting that describes a similar issue: http://www.theserverside.com/discussions/thread.tss?thread_id=22638
Problem
I have a database view that yields a result set that has no true primary key. I want to use Hibernate/Persistence to map this result set onto Java objects. Of course, because there is no PK, I cannot decorate any field with `@Id`. When deploying, Hibernate complains about the missing `@Id`. How can I work around this?