Trouble understanding/using the ForeignCollectionField in ORMLite

Question

What's the correct way to persist an object with an embedded foreign collection? Currently I am using the following but I get an error Could not create data element in dao if I am adding a "zoneplay" object to the customer zonePlays collection when the zonePlay already exists. Is there some sort of upsert method I should use to add to the foreign collection or do I need to check for existance somehow before the insert?

@DatabaseTable
public class Customer {

    @DatabaseField(id = true)
    public int id;

    @ForeignCollectionField(eager = true)
    public ForeignCollection<ZonePlay> zonePlays;

    @DatabaseField
    public String email;

    public Customer(String json) {
        final JSONArray  zonesJson = customerJson.getJSONArray("zoneplays");
        this.zonePlays = DatabaseHelper.getInstance(ctx).getCustomerDao().getEmptyForeignCollection("zonePlays");
        for (int i = 0; i < numZones; i++) {
            final JSONObject rawZone = zonesJson.getJSONObject(i);
            ZonePlay zp = new ZonePlay();
            zp.id = rawZone.getInt("id");
            zp.score = rawZone.getInt("score");
            zp.Customer = this;
            this.zonePlays.add(zp);
        }
    }

    @DatabaseTable
    public class ZonePlay {

        @DatabaseField(id = true)
        public int id;

        @DatabaseField(foreign=true)
        public Customer customer;
    }

Then I run this

Customer cust = new Customer(client.response);
DatabaseHelper db = DatabaseHelper.getInstance(getApplicationContext());
db.getDao(Customer.class).createOrUpdate(cust);

Answer 1

What's the correct way to persist an object with an embedded foreign collection?

The "correct" way may be to add the element using it's own DAO -- not through the foreign collection. This way you can use the createOrUpdate(...) method:

  Dao<ZonePlay, Integer> zoneDao = DatabaseHelper.getInstance(ctx).getZoneDao();
  for (int i = 0; i < numZones; i++) {
        final JSONObject rawZone = zonesJson.getJSONObject(i);
        ZonePlay zp = new ZonePlay();
        zp.id = rawZone.getInt("id");
        zp.score = rawZone.getInt("score");
        zp.Customer = this;
        zoneDao.createOrUpdate(zp);
  }

I get an error Could not create data element in dao if I am adding a "zoneplay" object to the customer zonePlays collection when the zonePlay already exists.

Right. If you are trying to add a ZonePlay to a Customer's foreign collection, this will try to add to the table. If a ZonePlay already exists in the table then this will throw an exception.