java - 使用子实体的默认提取组是否必然意味着 App Engine 上的非法加入？

Question

我尝试向我的 User 类添加一个属性，以使其自动加载其子记录(联系人)。

根据下面的错误，这似乎不可能，至少我尝试这样做的方式是这样:

 @Persistent(mappedBy = "user", defaultFetchGroup="true")
    private List<Contact> contacts;


WARNING: Meta-data warning for com.contactly.User.contacts: The datastore does not support joins and therefore cannot honor requ
ests to place related objects in the default fetch group.  The field will be fetched lazily on first access.  You can modify this warn
ing by setting the datanucleus.appengine.ignorableMetaDataBehavior property in your config.  A value of NONE will silence the warning.
  A value of ERROR will turn the warning into an exception.

在 JDO 中还有其他方法可以做到这一点吗？

Answer 1

没有。 App Engine 数据存储区不支持在加载查询结果的同时加载引用的实体。