diff --git a/Polyclinic/PolyclinicDataModels/IId.cs b/Polyclinic/PolyclinicDataModels/IId.cs
new file mode 100644
index 0000000..6f19389
--- /dev/null
+++ b/Polyclinic/PolyclinicDataModels/IId.cs
@@ -0,0 +1,7 @@
+namespace PolyclinicDataModels
+{
+    public interface IId
+    {
+        int Id { get; }
+    }
+}