reorganization of database layer

UserService.DatabaseLayer/DataModels/Node.cs

@@ -0,0 +1,62 @@
+#nullable enable
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
+namespace UserService.DatabaseLayer.DataModels
+{
+    public class OrganizationUnit : Node
+    {
+        public Member? Manager { get; set; }
+    }
+
+    public class SecurityGroup : Member
+    {
+
+    }
+
+    public class User : Member
+    {
+        public string? FirstName { get; set; }
+        public string? LastName { get; set; }
+        public bool IsActive { get; set; }
+
+        public string FullName => $"{FirstName} {LastName}";
+
+        public IEnumerable<UserMember> MemberOf { get; set; } = new List<UserMember>();
+
+        public User Clone() => (User)MemberwiseClone();
+    }
+
+    public class UserMember
+    {
+        public int MemberId { get; set; }
+        public Member? Member { get; set; }
+
+        public int UserId { get; set; }
+
+        public User? User { get; set; }
+    }
+
+    public abstract class Member : Node
+    {
+        [EmailAddress]
+        public string? EMail { get; set; }
+
+        public ICollection<UserMember> Members { get; set; } = new List<UserMember>();
+    }
+
+    public abstract class Node
+    {
+        public int Id { get; set; }
+        [Required] public string CommonName { get; set; } = null!;
+        public string? Description { get; set; }
+        public ICollection<Node> Children { get; set; } = new List<Node>();
+        public Node? Parent { get; set; } //Parent
+        public int? ParentId { get; set; }
+
+        public override string ToString()
+        {
+            return $"[{GetType().Name}] {Id:D5} {CommonName}";
+        }
+    }
+}