The associated query to multiple tables

[JinJieGu]

// Customer.java
@Entity
public class Customer {
 
    @Id public long id;
    public boolean male; 
    @Backlink
    public ToMany<Order> orders;
 
}
 
// Order.java
@Entity
public class Order {
 
    @Id public long id;
    public boolean isCash;
    public ToOne<Customer> customer;
 
}

If the tables like this, I want use the DataSubscription to observer the data which Customer is male and Order isCash? What should I do ？Thank you very much !

[greenrobot]

Sounds like you are wanting to do two (separate) queries?

[JinJieGu]

I want to get the customers(isMale) 's orders(isCash), so I don't know how to write the DataSubscription

[JinJieGu]

Do objectBox support multiple table queries like SQL?

[greenrobot]

At the moment we do not offer much convenience here for cases like yours (feature requests are pending).

This would be how you get the data, put this in some method:

long customerIds[] = customerBox.query().equal(Customer_.male, true).build().findIds();
List<Order> orders = orderBox.query().equal(Order_.isCash, true).in(Order_.customerId, customerIds).build().find();

Then you would subscribe to changes of those to classes using a general subscribe call:

boxStore.subscribe().observer(new DataObserver<Class>() { ...});

In your DataObserver implementation you should check if the class is either Customer or Order and in that case call your method triggering the method with the query.

This is not optimal and we are working on reducing the amount of required code, but it should work.

[jrcacd]

We need the same for many-to-many query

[greenrobot-team]

Please vote for #59.