using LinqToDB.Mapping; using System; namespace SeniorAssistant.Models { public class Heartbeat : IHasTime { [PrimaryKey] [NotNull] [Association(ThisKey = nameof(Username), OtherKey = nameof(User.Username), CanBeNull = false)] public string Username { get; set; } [PrimaryKey] [NotNull] public DateTime Time { get; set; } public double Value { get; set; } } }