JPA Hibernate - 导致具有多对多关联的非实体

Question

I have an entities:

1. Player
2. Team

There is many-to-many association between Player and Team.

Player and Team entities are big so we want to fetch all Player entities in lightweight Pojo with only few attributes. But we need team info too.

USE CASE display all players (for example 1500 players) in table with following info

Player name | Player surname | Teams

This is code we use now:

                "SELECT new pojos.PlayerPojo(e.id, e.firstName, e.lastName, t.id, t.name) " +
                        "FROM Player e LEFT JOIN e.teams t");

Problem with this query is that we get multiple rows if player has multiple teams, then we need to iterate through all entities and join them in Java, which is performance issue. We want to have snappy app. We cannot use Entity class as it is too big and we have performance issues and memory issues (we are limited with our cloud plans)

Answer 1

maybe you could provide two Entity that keep the require fields, and put the ManyToOne/OneToMany annotation in these entity class so you can enjoy all the features in hibernate Conveniently without write hsql.