Looking for some advice here.

I use a JPA wrapper that calls the create method which is the em.persist transaction. This loads all new records into the database when the database is empty.
These records get updated every 15 min from the server.
I have set a primary key on one of the fields so that their is no duplication of records.

If the data has changed since the first call - I want it to load the data into the database as new records. I do not want it to update the existing records.

How would I go about this ?

Any advice ??