--- loncom/interface/loncoursedata.pm	2016/08/14 16:13:21	1.200
+++ loncom/interface/loncoursedata.pm	2016/08/16 00:46:58	1.201
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: loncoursedata.pm,v 1.200 2016/08/14 16:13:21 raeburn Exp $
+# $Id: loncoursedata.pm,v 1.201 2016/08/16 00:46:58 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -1423,14 +1423,62 @@ sub ensure_current_sections {
         $updatetime = $tableinfo{'Update_time'};
     }
     if ((!defined($updatetime)) || ($modifiedtime > $updatetime)) {
-        if (&Apache::lonmysql::drop_table($student_table)) {
-            if (&init_dbs($courseid)) {
-                return "error creating $student_table\n";
-            } else {
-                &populate_student_table($courseid);
+        &update_student_table($cdom,$cnum);
+    }
+    return;
+}
+
+sub update_student_table {
+    my ($cdom,$cnum) = @_;
+    return unless (($cdom ne '') && ($cnum ne ''));
+    my (%roster,%sqldata);
+    my $classlist = &get_classlist($cdom,$cnum);
+    while (my ($student,$data) = each (%$classlist)) {
+        my ($section,$start,$end) = ($data->[&CL_SECTION()],
+                                     $data->[&CL_START()],
+                                     $data->[&CL_END()]);
+        if ($section eq '' || $section =~ /^\s*$/) {
+            $section = 'none';
+        }
+        if ($start eq '') { $start = 0; }
+        if ($end eq '')   { $end   = 0; }
+        $roster{$student}{'section'} = $section;
+        $roster{$student}{'start'} = $start;
+        $roster{$student}{'end'} = $end;
+    }
+    my $dbh = &Apache::lonmysql::get_dbh();
+    my $statement = "SELECT student_id,student,section,start,end FROM $student_table";
+    my $sth = $dbh->prepare($statement);
+    $sth->execute();
+    if ($sth->err()) {
+        &Apache::lonnet::logthis("Unable to execute MySQL request:");
+        &Apache::lonnet::logthis("\n".$statement."\n");
+        &Apache::lonnet::logthis("error is:".$sth->errstr());
+        return undef;
+    }
+    foreach my $row (@{$sth->fetchall_arrayref}) {
+        my ($id,$student,$section,$start,$end) = (@$row);
+        if (ref($roster{$student}) eq 'HASH') {
+            if (($roster{$student}{'section'} ne $section) ||
+                ($roster{$student}{'start'} ne $start) ||
+                ($roster{$student}{'end'} ne $end)) {
+                $sqldata{$id} = {
+                                  section => $roster{$student}{'section'},
+                                  start   => $roster{$student}{'start'},
+                                  end     => $roster{$student}{'end'},
+                                };
             }
         }
     }
+    $sth->finish();
+    if (keys(%sqldata)) { 
+        foreach my $id (sort { $a <=> $b } keys(%sqldata)) {
+            my $request = "UPDATE $student_table SET section='$sqldata{$id}{section}'".
+                          ", start='$sqldata{$id}{start}'".
+                          ", end='$sqldata{$id}{end}' WHERE student_id='$id'";
+            $dbh->do($request);
+        }
+    }
     return;
 }