diff --git a/postgresql/update/W2025-16.sql b/postgresql/update/W2025-16.sql
new file mode 100644
index 0000000000..26403f6fa1
--- /dev/null
+++ b/postgresql/update/W2025-16.sql
@@ -0,0 +1,13 @@
+
+-- Add unique constraint
+ALTER TABLE item_type_mapping
+ADD CONSTRAINT uq_item_type_mapping_item_type_id UNIQUE (item_type_id);
+
+-- Add foreign key constraint
+ALTER TABLE item_type_mapping
+ADD CONSTRAINT fk_item_type_mapping_item_type_id_item_type
+FOREIGN KEY (item_type_id) REFERENCES item_type(id) ON DELETE CASCADE;
+
+-- Drop indexes
+DROP INDEX IF EXISTS idx_created_item_type_mapping;
+DROP INDEX IF EXISTS idx_item_type_id_item_type_mapping;