diff --git a/spec/db-cars.cr b/spec/db-cars.cr
index f65c52c..f360c70 100644
--- a/spec/db-cars.cr
+++ b/spec/db-cars.cr
@@ -7,9 +7,9 @@ require "./spec-database.cr"
 class Car
 	include JSON::Serializable
 
-	property name     : String        # unique to each instance (1-1 relations)
-	property color    : String        # a simple attribute (1-n relations)
-	property keywords : Array(String) # tags about a car, example: "shiny" (n-n relations)
+	property name     : String # unique to each instance (1-1 relations)
+	property color    : String        | DODB::NoIndex # a simple attribute (1-n relations)
+	property keywords : Array(String) | DODB::NoIndex # tags about a car, example: "shiny" (n-n relations)
 
 	def_clone
 
@@ -31,27 +31,27 @@ class Car
 end
 
 def ram_indexes(storage : DODB::Storage)
-	n = storage.new_RAM_index "name", &.name
-	c = storage.new_RAM_partition "color", &.color
-	k = storage.new_RAM_tags "keyword", &.keywords
+	n = storage.new_nilable_RAM_index "name", &.name
+	c = storage.new_nilable_RAM_partition "color", &.color
+	k = storage.new_nilable_RAM_tags "keyword", &.keywords
 	return n, c, k
 end
 
 def cached_indexes(storage : DODB::Storage)
-	n = storage.new_index "name", &.name
-	c = storage.new_partition "color", &.color
-	k = storage.new_tags "keyword", &.keywords
+	n = storage.new_nilable_index "name", &.name
+	c = storage.new_nilable_partition "color", &.color
+	k = storage.new_nilable_tags "keyword", &.keywords
 	return n, c, k
 end
 
 def uncached_indexes(storage : DODB::Storage)
-	n = storage.new_uncached_index "name", &.name
-	c = storage.new_uncached_partition "color", &.color
-	k = storage.new_uncached_tags "keyword", &.keywords
+	n = storage.new_nilable_uncached_index "name", &.name
+	c = storage.new_nilable_uncached_partition "color", &.color
+	k = storage.new_nilable_uncached_tags "keyword", &.keywords
 	return n, c, k
 end
 
-def add_cars(storage : DODB::Storage, nb_iterations : Int32, from = 0)
+def add_cars(storage : DODB::Storage, nb_iterations : Int32, from = 0, max_it_tags = 5000)
 	i = from
 	car1 = Car.new "Corvet", "red", [ "shiny", "impressive", "fast", "elegant" ]
 	car2 = Car.new "Bullet-GT", "blue", [ "shiny", "fast", "expensive" ]
@@ -66,11 +66,25 @@ def add_cars(storage : DODB::Storage, nb_iterations : Int32, from = 0)
 		car4.name = "Ford-5-#{i}"
 		car5.name = "C-MAX-#{i}"
 
-		storage << car1
-		storage << car2
-		storage << car3
-		storage << car4
-		storage << car5
+		if i >= max_it_tags
+			car1.color = DODB.no_index
+			car2.color = DODB.no_index
+			car3.color = DODB.no_index
+			car4.color = DODB.no_index
+			car5.color = DODB.no_index
+
+			car1.keywords = DODB.no_index
+			car2.keywords = DODB.no_index
+			car3.keywords = DODB.no_index
+			car4.keywords = DODB.no_index
+			car5.keywords = DODB.no_index
+		end
+
+		storage << car1.clone
+		storage << car2.clone
+		storage << car3.clone
+		storage << car4.clone
+		storage << car5.clone
 		i += 1
 		#STDOUT.write "\radding value #{i}".to_slice
 	end