Flexible relations based on non-ID properties

another thing i think need, define custom property from source and target to realtion, example :

@Entity
public class Customer {
    @Id private Long id;
    private String tag;
 
    @Backlink(joinProperties = {
        @JoinProperty(name = "tag", referencedName = "customerTag")
    })
    private ToMany<Order> orders;
}
 
@Entity
public class Order {
    @Id private Long id;
    private String customerTag;
}

首先查看 Java 实体示例以及其中对 @Backlink 和 @JoinProperty 的使用。所请求的行为是让一个 relation 将 Customer.tag 与 Order.customerTag 连接起来，而不是连接 IDs；支持这种 custom-property relation 即表示完成，但 issue 未指明任何文件或测试。