diff --git a/etc/schema/mysql/mysql.schema.sql b/etc/schema/mysql/mysql.schema.sql
index 53b3d5e5..566619d1 100644
--- a/etc/schema/mysql/mysql.schema.sql
+++ b/etc/schema/mysql/mysql.schema.sql
@@ -858,8 +858,8 @@ CREATE TABLE downtime_history (
   flexible_duration bigint(20) unsigned NOT NULL,
   scheduled_start_time bigint(20) unsigned NOT NULL,
   scheduled_end_time bigint(20) unsigned NOT NULL,
-  start_time bigint(20) unsigned DEFAULT NULL COMMENT 'Time when the host went into a problem state during the downtimes timeframe',
-  end_time bigint(20) unsigned DEFAULT NULL COMMENT 'Problem state assumed: scheduled_end_time if fixed, start_time + duration otherwise',
+  start_time bigint(20) unsigned NOT NULL COMMENT 'Time when the host went into a problem state during the downtimes timeframe',
+  end_time bigint(20) unsigned NOT NULL COMMENT 'Problem state assumed: scheduled_end_time if fixed, start_time + duration otherwise',
   has_been_cancelled enum('y', 'n') NOT NULL,
   trigger_time bigint(20) unsigned NOT NULL,
   cancel_time bigint(20) unsigned NULL DEFAULT NULL,