Question

I have two entities: EntityA and EntityB. EntityB has a foreign field of EntityA:

@DatabaseField(foreign=true, columnName=ENT_A_NAME)
private EntityA entityA;

Now I want to query all entries of EntityB where EntityA is null. So I’ve made the following query:

bDao.queryBuilder().where().isNull(EntityB.Ent_A_NAME).prepare();

If I execute the query I get an empty result set back.

If I execute queryAll() I see that the entries of EntityB have always an associated Order-Object with all values set to null/0.

How can I execute my query?

Answer 1

I’m not sure @Toni4780. The following test case works for me. I don’t see anything that you are doing wrong.

In the table for EntityB, ORMLite actually stores the id of the EntityA so I am wondering if it is null or 0. Have you tried the following?

bDao.queryBuilder().where().eq(EntityB.Ent_A_NAME, 0).prepare();

or both:

bDao.queryBuilder().where().isNull(EntityB.Ent_A_NAME).
    or().eq(EntityB.Ent_A_NAME, 0).prepare();

Here’s my unit test code that works:

Dao<Order, Integer> orderDao =
    DaoManager.createDao(connectionSource, Order.class);
TableUtils.createTable(connectionSource, Order.class);
int numOrders = 10;
for (int orderC = 0; orderC < numOrders; orderC++) {
    Order order = new Order();
    order.val = orderC;
    assertEquals(1, orderDao.create(order));
}
List<Order> results = orderDao.queryBuilder().where()
    .isNull(Order.ACCOUNT_FIELD_NAME).query();
assertNotNull(results);
assertEquals(numOrders, results.size());