MongoDB relashionships+SpringBoot REST API+POST Method - spring

Question

I used SpringBoot REST API Microservices with MongoDB.
I have three services such as player, game and score.
For each services I have a MongoDB databases.
In the POST Method in the Score service, I check if the plyare and game exist, then for existed a player and a game, create a new score.
for doing this, at first I used player-repository and game-repository for checking they are exist or not but after that I read some documents about Relashionships(OneToMany, ManyToOne) and about Refrence, #DBRef, and I tried using them.
The problem is for example in the relationships, I am interested in to have just the variable nickname which is ID in the Player Class and the variable code which is ID in the Game Class and not other variables, instead, in the Score Class when I define
private Player player;
I have an object of Player class with all its member variables, and it is the same situation for game.
I am interested in this form for Score:
## player
{
“nickname”: “pippo”,
“firstname”: “Filippo”,
“lastname”: “Rossi”,
“email”: “filipporox#mail.com”
}
## game
{
“code”: “XFR453”,
“title”: “The Game”,
“softwarehouse”: “SWGameS”,
“version”: “1”,
“releaseyear”: “2020”
}
***## score
{
“player”: “pippo”,
“game”: “XFR453”,
“score”: “232209”,
“date”: “2020/04/28”,
“history”: [
{ “score”: “232209”, “date”: “2020/04/28” },
{ “score”: “220011”, “date”: “2020/04/23” },
{ “score”: “182210”, “date”: “2020/03/12” }
]
}***
could you help me how can I deal the above example?
Score Class:
#Document(collection = "score")
public class Score {
#Id
#NotBlank
#JsonView(Views.class)
private String scoreid;
#JsonView(Views.class)
private Long score;
#JsonView(Views.class)
private Date date;
#NotBlank
#JsonView(Views.class)
private Player player;
#NotBlank
#JsonView(Views.class)
private Game game;
public List<String> history;
public String getScoreid() {
return scoreid;
}
public void setScoreid(String scoreid) {
this.scoreid = scoreid;
}
public Long getScore() {
return score;
}
public void setScore(Long score) {
this.score = score;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
public Player getPlayer() {
return player;
}
public void setPlayer(Player player) {
this.player = player;
}
public Game getGame() {
return game;
}
public void setGame(Game game) {
this.game = game;
}
public List<String> getHistory() {
return history;
}
public void setHistory(List<String> history) {
this.history = history;
}
}
sorry for my bad English.