diff --git a/mod/exercise/db/mysql.php b/mod/exercise/db/mysql.php
index 03e75ffd5a8..50388c00cd8 100644
--- a/mod/exercise/db/mysql.php
+++ b/mod/exercise/db/mysql.php
@@ -30,6 +30,10 @@ function exercise_upgrade($oldversion) {
 		table_column("exercise", "", "password", "VARCHAR", "32", "", "", "NOT NULL");
     }
 
+    if ($oldversion < 2004091000) {
+        table_column("exercise_assessments","generalcomment","generalcomment","text","","","","NOT NULL");
+        table_column("exercise_assessments","teachercomment","teachercomment","text","","","","NOT NULL");
+    }
     return true;
 }
 
diff --git a/mod/exercise/db/mysql.sql b/mod/exercise/db/mysql.sql
index def08688c42..d15b518903a 100644
--- a/mod/exercise/db/mysql.sql
+++ b/mod/exercise/db/mysql.sql
@@ -57,8 +57,8 @@ CREATE TABLE `prefix_exercise_assessments` (
   `grade` float NOT NULL default '0',
   `gradinggrade` int(3) NOT NULL default '0',
   `mailed` tinyint(2) unsigned NOT NULL default '0',
-  `generalcomment` text NOT NULL,
-  `teachercomment` text NOT NULL,
+  `generalcomment` text NOT NULL default '',
+  `teachercomment` text NOT NULL default '',
    PRIMARY KEY  (`id`),
    INDEX (`submissionid`),
    INDEX (`userid`) 
diff --git a/mod/exercise/db/postgres7.php b/mod/exercise/db/postgres7.php
index 1fdbb5ec759..950d3359561 100644
--- a/mod/exercise/db/postgres7.php
+++ b/mod/exercise/db/postgres7.php
@@ -20,6 +20,10 @@ function exercise_upgrade($oldversion) {
         table_column("exercise", "", "password", "VARCHAR", "32", "", "", "NOT NULL");
     }
 
+    if ($oldversion < 2004091000) {
+        table_column("exercise_assessments","generalcomment","generalcomment","text","","","","NOT NULL");
+        table_column("exercise_assessments","teachercomment","teachercomment","text","","","","NOT NULL");
+    }
 
     return true;
 }
diff --git a/mod/exercise/db/postgres7.sql b/mod/exercise/db/postgres7.sql
index 387d8c23add..0483624902a 100644
--- a/mod/exercise/db/postgres7.sql
+++ b/mod/exercise/db/postgres7.sql
@@ -55,8 +55,8 @@ CREATE TABLE prefix_exercise_assessments (
   grade float NOT NULL default '0',
   gradinggrade INT NOT NULL default '0',
   mailed INT2  NOT NULL default '0',
-  generalcomment text NOT NULL,
-  teachercomment text NOT NULL
+  generalcomment text NOT NULL default '',
+  teachercomment text NOT NULL default ''
   );
 # --------------------------------------------------------
 CREATE INDEX prefix_exercise_assessments_submissionid_idx ON prefix_exercise_assessments (submissionid);
diff --git a/mod/exercise/version.php b/mod/exercise/version.php
index bf291f84db2..9a13129a2c8 100644
--- a/mod/exercise/version.php
+++ b/mod/exercise/version.php
@@ -5,7 +5,7 @@
 //  This fragment is called by /admin/index.php
 ////////////////////////////////////////////////////////////////////////////////
 
-$module->version  = 2004090200;
+$module->version  = 2004091000;
 $module->requires = 2004052505;  // Requires this Moodle version
 $module->cron     = 60;