MyTaskDataAccess.cs
using SQLite;
using System.Collections.Generic;
using System.Threading.Tasks;
using TMApp.Models;

namespace TMApp.Data
{
	public class MyTaskIDataAccess
	{
		private static SQLiteAsyncConnection _database;

		public MyTaskIDataAccess()
		{
			_database = new TMASQLiteDatabase().GetConnectionAsync();
			_database.CreateTableAsync<MyTask>().Wait();
		}

		public Task<List<MyTask>> GetAllAsync()
		{
			return _database.Table<MyTask>().ToListAsync();
		}

		public Task<List<MyTask>> GetAllOrderByTitleAsync()
		{
			return _database.QueryAsync<MyTask>("SELECT * FROM MyTask ORDER BY Title");
		}

		public Task<List<MyTask>> GetNotDoneAsync()
		{
			return _database.Table<MyTask>().Where(t => t.IsDone == false).ToListAsync();
		}

        public Task<List<MyTask>> GetNotDoneOrderByTitleAsync()
        {
            return _database.QueryAsync<MyTask>("SELECT TaskId, " +
                "Title, Description, IsDone " +
                "FROM MyTask " +
                "WHERE IsDone=0 " +
                "ORDER BY Title");
        }

        public Task<MyTask> FindByAsync(int id)
		{
			return _database.Table<MyTask>().Where(t => t.TaskId == id).FirstOrDefaultAsync();
		}

		public Task<int> AddAsync(MyTask obj)
		{
			return _database.InsertAsync(obj);
		}

		public Task<int> UpdateAsync(MyTask obj)
		{
			return _database.UpdateAsync(obj);
		}

		public Task<int> DeleteAsync(int id)
		{
			return _database.DeleteAsync<MyTask>(id);
		}
	}
}
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TMASQLiteDatabase.cs
using SQLite;
using System;
using System.IO;

namespace TMApp.Data
{
	public sealed class TMASQLiteDatabase
    {
		private SQLiteAsyncConnection _database;

		public SQLiteAsyncConnection GetConnectionAsync()
		{
			if(_database is null)
				_database = new SQLiteAsyncConnection(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "TMAdb.SQLite3"));
			return _database;
		}
	}
}
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MyTask.cs
using SQLite;
using System;

namespace TMApp.Models
{
	public class MyTask
    {
		[PrimaryKey, AutoIncrement]
		public Int32 TaskId { get; set; }
		public String Title { get; set; }
		public String Description { get; set; }
		public Boolean IsDone { get; set; }
	}
}