Question

I have the following set of classes

@Embeddable
public class SharedClass {
    ...
    private String legacyField;
    ...
}

@Entity
public class LongStandingEntity {
    ...
    private SharedClass sharedClass;
    ...
}

Where legacyfield stores some obsolete data in older objects but is not collected for new ones. However I do need to able to continue to access the old data.

I’m creating a new entity that also makes use of SharedClass

@Entity
public class NewEntity {
    ...
    private SharedClass sharedClass;
    ...
}

It doesn’t need legacyField and I’d like to avoid having to add a column in the database for it whilst keeping the mapping working for LongStandingEntity.

Is this possible with JPA annotations?

Answer 1

I don’t recall a particular annotation that can help you with that. Still I’d rather take a design approach with this situation. If you have field that belongs only to a certain class separate them in another embedabble class that’s associated only with the older data.

Seems like a cleaner approach to me, just to keep entities clearly differenciated.