使用 ObjectBox 存储一对多关系列表？

Question

I get a json like below from server:

  { "customers": [
    {
        "customer_name": "name1",
        "orders_list": [
            {
                "order_id": "1111111",
                "order_type": "a",
                "order_date": "11/02/2020 "
            },
            {
                "order_id": "1111112",
                "order_type": "b",
                "order_date": "11/02/2020 "
            },
            {
                "order_id": "1111113",
                "order_type": "c",
                "order_date": "11/02/2020 "
            }
        ]
    },
    //more customers
]

}

I get it using Retrofit and want to store it with Objectbox.

Customer entity:

  @Entity
public class Customer {

    @Id long id;

    @SerializedName("customer_name")
    private String  customer_name;

    @SerializedName("array_of_matchs")
    @Transient
    public List<Order> orders_list;

    @Backlink
    public ToMany<Order> orders;

   //constructor , getters , setters ,...
}

Order Entity:

public class Order {

    @Id
    public long id;

    @SerializedName("order_id")
    private int  order_id;

    @SerializedName("order_type")
    private String  order_type;

    @SerializedName("order_date")
    private String  order_date;

    public ToOne<Customer> customer;
  //constructor , getters , setters ,...
}

Gson convertor returns a List of Customer s with all his orders.I tried to store customers as below :

  customersBox.put(list_of_customers_get_from_retrofit);

And orders :

for (Customer each_customer : list_of_customers_get_from_retrofit ) {
      orderBox.put(each_customer.orders_list);
}

Then when i checked boxes with Data Browser ,all customerToOneRelationId s set to 0 . What's wrong with that?

In such case, how do we make a relation between the customer and his Order s List? How to store orders in right way?

Answer 1

I have to set targets manually :

 for (Customer each_customer : list_of_customers_get_from_retrofit ) {
     for (Order each_order : each_customer.orders_list ) {
       each_order.customer.setTarget(each_customer);
       orderBox.put(each_order);
     }
}

Thanks to this repository (This is useful for any Objectbox newbie like me).