diff --git a/server.rb b/server.rb
index 54cf8ab..f3b6fe3 100755
--- a/server.rb
+++ b/server.rb
@@ -267,9 +267,13 @@ def add_part(part)
   fields_txt = ["name", "description", "details", "mpn", "package", "datasheet", "page"];
   fields_txt.each do |field|
     next unless part[field]
-    next if family and family[field] == part[field]
-    update = @db.prepare("UPDATE part SET #{field} = ? WHERE id = ?")
-    update.execute(part[field], part["id"])
+    if family and family[field] == part[field] then
+      update = @db.prepare("UPDATE part SET #{field} = NULL WHERE id = ?")
+      update.execute(part["id"])
+    else
+      update = @db.prepare("UPDATE part SET #{field} = ? WHERE id = ?")
+      update.execute(part[field], part["id"])
+    end
   end
   # update manufacturer and package
   field_ref = ["manufacturer"]