Advice wanted - SPRING JPA JoinColumns

Just started exploring SPRING and JPA. So bear with me, please.



Lets assume I have two tables

EMPLOYEE TABLE                  ATTACHMENT TABLE
---------------------------     -------------------------------------------
ID | FIRSTNAME | LASTNAME |     ID  |  REF_TYPE  | REF_ID | FILE
---------------------------     -------------------------------------------
1  | EMP1      | EMPL1    |     1   | "EMPLOYEE" | 1      | EMPL1_FIle1.jpg
---------------------------     -------------------------------------------
2  | EMP2      | EMPL2    |     2   | "EMPLOYEE" | 1      | EMPL1_FIle2.jpg
                                -------------------------------------------
                                3   | "EMPLOYEE" | 2      | EMPL2_FIle1.jpg

** To keep attachments flexible (so I can reuse the same table/class for other places where I need attachments), I use a combination of REF_TYPE and REF_ID to locate the referencing Object.

What would be the best way to do this?

- Should be even doing this? Is there a better approach to the DB/Class design?



- Should I use @JoinColumns? (But I am not sure how that would work...)



- Or should the logic to load attachments go into a Service/DAO class with a findByRefTypeAndRefId(String refType, long refId) function falling back to a JPARepository @Autowired interface?