add constraints for member-user and member-property

lib/accounts/user.ex

@@ -12,6 +12,12 @@ defmodule Mv.Accounts.User do
   postgres do
     table "users"
     repo Mv.Repo
+
+    references do
+      # When a member is deleted, set the user's member_id to NULL
+      # This allows users to continue existing even if their linked member is removed
+      reference :member, on_delete: :nilify
+    end
   end
 
   @doc """

lib/membership/property.ex

@@ -42,4 +42,10 @@ defmodule Mv.Membership.Property do
   calculations do
     calculate :value_to_string, :string, expr(value[:value] <> "")
   end
+
+  # Ensure a member can only have one property per property type
+  # For example: A member can have only one "email" property, one "phone" property, etc.
+  identities do
+    identity :unique_property_per_member, [:member_id, :property_type_id]
+  end
 end