如何在 Google App Engine 应用中使用 objectify 进行查询

Question

I have one entity called MemberInfo and another entity called PaymentInfo.

@Parent
@Index
private Key<MemberInfo> memberInfo;
private double aCharges;
private double bCharges;
private double cCharges;

//And my query is as below

 Query<PaymentInfo> query = OfyService.ofy().load().type(PaymentInfo.class);
        Key<PaymentInfo> memberInfoKey = Key.create(PaymentInfo.class,membershipId);
        query = query.filter("=", memberInfoKey);
        return query.list();

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Above is code that I have written but I am getting null result. I want result from PaymentInfo entity whose memberId is in Member entity

I want to query on PaymentInfo and get result of different payments paid by particular Member using memberId in MemberInfo in PaymentInfo. I have different fields like charges and one more field as @Parent Key<MemberInfo> .

Answer 1

I think you may need to add the name of the field that you are filtering on in your filter call, so query.filter("=", memberInfoKey) would become query.filter("memberInfo", memberInfoKey)

This is how I've managed to get it working before, and here are the docs with some more examples