Association in user

SeniorAssistant/Models/Users/User.cs

@@ -1,5 +1,6 @@
 using LinqToDB.Mapping;
 using Newtonsoft.Json;
+using SeniorAssistant.Models.Users;
 
 namespace SeniorAssistant.Models
 {
@@ -8,15 +9,27 @@ namespace SeniorAssistant.Models
         [Column(IsPrimaryKey = true, CanBeNull = false)]
         public string Username { get; set; }
 
-        [NotNull]
+        [Column(CanBeNull = false)]
         public string Email { get; set; }
 
-        [NotNull]
         [JsonIgnore]
+        [Column(CanBeNull = false)]
         public string Password { get; set; }
         
         public string Name { get; set; }
-
+        
         public string LastName { get; set; }
+
+        [JsonIgnore]
+        [Association(ThisKey = nameof(Username), OtherKey = nameof(Doctor.Username), CanBeNull = true)]
+        public Doctor Doc { get; set; }
+
+        [JsonIgnore]
+        [Association(ThisKey = nameof(Username), OtherKey = nameof(Patient.Username), CanBeNull = true)]
+        public Patient Pat { get; set; }
+
+        public bool IsDoctor() => Doc != null;
+
+        public bool IsPatient() => Pat != null;
     }
 }