DBManager.cs

using System.Collections;
using UnityEngine;

public static class DBManager
{
    public static string username;
    public static string email;
    public static int score;
    
    public static int GetScore()
    {
        return score;
    }

    public static string GetUsername()
    {
        return username;
    }

    public static string GetEmail()
    {
        return email;
    }
}

LeaderboardController.cs

using Unisave.Facades;
using UnityEngine;

public class LeaderboardController : MonoBehaviour
{
    // player name & player score
    private string username, email;
    private int score;
    
    void Start()
    {
        LoadLeaderboard();
    }
    
    
    // Downloads the latest leaderboard from the server and displays it.
    async void LoadLeaderboard()
    {
        LeaderboardEntity entity = await OnFacet<LeaderboardFacet>
            .CallAsync<LeaderboardEntity>(
                nameof(LeaderboardFacet.GetLeaderboard)
            );
    }

    public async void AddRecord()
    {
        LeaderboardEntity entity = await OnFacet<LeaderboardFacet>
            .CallAsync<LeaderboardEntity>(
                nameof(LeaderboardFacet.AddRecord),
                DBManager.GetUsername(), DBManager.GetEmail(),
                DBManager.GetScore().ToString()
            ); 
        
        DisplayLeaderboardEntity(entity);
    }
  
    // Displays a given leaderboard to the console.
    private void DisplayLeaderboardEntity(LeaderboardEntity entity)
    {
        Debug.Log("## Leaderboard ##");
        foreach (var record in entity.records)
        {
            Debug.Log($" {record.username} | {record.score} points | {record.email} | {entity.EntityId} |");
        }

        if (entity.records.Count == 0)
        {
            Debug.Log("Empty leaderboard");
        }
    }

    /*
    #region New LeaderboardController
    public async void DownloadLeaderboardFromServer(string username)
    {
        LeaderboardResponse response = await OnFacet<LeaderboardFacet>
            .CallAsync<LeaderboardResponse>(
                nameof(LeaderboardFacet.DownloadLeaderboard), username
            );
    }    
    #endregion
    */
}

LeaderboardEntity.cs

using System;
using System.Collections;
using System.Collections.Generic;
using Unisave;
using Unisave.Entities;
using Unisave.Facades;

public class LeaderboardEntity : Entity
{
    public class LeaderboardRecord
    {
        public string username, email;
        public int score;
    }

    public List<LeaderboardRecord> records = new List<LeaderboardRecord>();
}

LeaderboardFacet.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using Unisave;
using Unisave.Facets;
using Unisave.Facades;
using Unisave.Authentication.Middleware;
using Unisave.Entities;

public class LeaderboardFacet : Facet
{

    #region LeaderboardFacet v1
    
    // Sends the only leaderboard in the database to the client.
    // If no leaderboard entity exists, it gets automatically created.
    public LeaderboardEntity GetLeaderboard()
    {
        return DB.FirstOrCreate<LeaderboardEntity>();
    }
    
    // Some player has scored, lets add them to the leaderboard
    // (and then remove during truncation if the score isn't high enough)
    public LeaderboardEntity AddRecord(string username, string email, int score)
    {
        // get the leaderboard entity
        var leaderboard = DB.FirstOrCreate<LeaderboardEntity>();
        
        // add the record
        leaderboard.records.Add(new LeaderboardEntity.LeaderboardRecord() {
            username = username,
            email = email,
            score = score
        });
        
        leaderboard.records = leaderboard.records
            .OrderByDescending(r => r.score) // sort the records by score
            .Take(100) // take only the top 100 players (truncate top 100)
            .ToList(); // convert to list and assign it to the leaderboard entity

        // save the leaderboard entity to database
        leaderboard.Save();

        // send the new leaderboard to the client
        return leaderboard;
    }
    #endregion
}