diff --git a/database/migrations/2025_09_22_133425_create_class_characteristics_table.php b/database/migrations/2025_09_22_133425_create_class_characteristics_table.php
index c220def..7874c56 100644
--- a/database/migrations/2025_09_22_133425_create_class_characteristics_table.php
+++ b/database/migrations/2025_09_22_133425_create_class_characteristics_table.php
@@ -142,7 +142,7 @@ return new class extends Migration
                 zmm_type                            TEXT DEFAULT NULL,
                 zmm_usp                             TEXT DEFAULT NULL,
                 mark_status                         TEXT DEFAULT NULL,
-                marked_datetime                     TIMESTAMP DEFAULT NULL,
+                marked_datetime                     TIMESTAMP NOT NULL DEFAULT NOW(),
                 marked_physical_count				TEXT DEFAULT '0',
                 marked_expected_time				TEXT DEFAULT '0',
                 marked_by                           TEXT DEFAULT NULL,