SQL query in Google App Engine in Java?

Question

I have to get all the entities in Google Datastore that fulfill a particular criteria

I have 3 fields:

marks1, marks2, marks3

I want the entities that have marks greater than 60 in all the fields

but since datastore allows inequality operator on a single field.

How can I bypass that.. Please suggest a solution that is not memory or processor intensive.

Answer 1

在您的实体中添加一个布尔属性allMarksGreaterThan60，并在每次标记之一更改时重新计算其值。

Answer 2

Alternatively, cou can now use Google Cloud Sql. See https://developers.google.com/cloud-sql/docs/developers_guide_java for information on how to get up and running on Java. It's basically managed MySQL using standard jdbc to talk to App Engine.