diff --git a/www/admin/class_test.php b/www/admin/class_test.php
index 8fe6f66e..63cfeac8 100644
--- a/www/admin/class_test.php
+++ b/www/admin/class_test.php
@@ -89,13 +89,14 @@
 	# db write class test
 	$table = 'foo';
 	$primary_key = ''; # unset
-	$db_write_table = array ('test');
+	$db_write_table = array ('test', 'some_bool');
+//	$db_write_table = array ('test');
 	$object_fields_not_touch = array ();
 	$object_fields_not_update = array ();
-	$data = array ('test' => 'SOMETHING '.time());
+	$data = array ('test' => 'BOOL TEST SOMETHING '.time());
 	$primary_key = $basic->db_write_data_ext($db_write_table, $primary_key, $table, $object_fields_not_touch, $object_fields_not_update, $data);
 	print "Wrote to DB tabel $table and got primary key $primary_key<br>";
-	$data = array ('test' => '');
+	$data = array ('test' => 'BOOL TEST OFF '.time(), 'some_bool' => 1);
 	$primary_key = $basic->db_write_data_ext($db_write_table, $primary_key, $table, $object_fields_not_touch, $object_fields_not_update, $data);
 	print "Wrote to DB tabel $table and got primary key $primary_key<br>";
 
diff --git a/www/libs/Class.DB.IO.inc b/www/libs/Class.DB.IO.inc
index 1be4d854..258b3423 100644
--- a/www/libs/Class.DB.IO.inc
+++ b/www/libs/Class.DB.IO.inc
@@ -1707,13 +1707,17 @@ $this->debug('ExecuteData', 'ERROR in STM['.$stm_name.'|'.$this->prepare_cursor[
 				if ((!$primary_key['value'] || ($primary_key['value'] && !in_array($field, $not_write_update_array))) && !in_array($field, $not_write_array))
 				{
 					// data from external or data field
-					$_data = (count($data) >= 1) ? $data[$field] : $GLOBALS[$field];
+					$_data = null;
+					if (count($data) >= 1 && array_key_exists($field, $data))
+						$_data = $data[$field];
+					elseif (array_key_exists($field, $GLOBALS))
+						$_data = $GLOBALS[$field];
 					$has_default = $table_data[$field]['has default'];
 					$not_null = $table_data[$field]['not null'];
 					// we detect bool, so we can force a write on "false"
 					$is_bool = $table_data[$field]['type'] == 'bool' ? true : false;
-					// write if the field has to be not null, or if there is no data and the field has no default values or if there is data
-					if (($not_null && !$_data) || (!$has_default && !$_data) || ($is_bool && !$_data) || (is_numeric($_data) && isset($_data)) || ($primary_key['value'] && !$_data) || $_data)
+					// write if the field has to be not null, or if there is no data and the field has no default values or if there is data or if this is an update and there is no data (set null)
+					if (($not_null && !$_data) || (!$has_default && !$_data) || (is_numeric($_data) && isset($_data)) || ($primary_key['value'] && !$_data) || $_data)
 					{
 						if ($q_sub_value && !$primary_key['value'])
 							$q_sub_value .= ', ';
@@ -1728,9 +1732,10 @@ $this->debug('ExecuteData', 'ERROR in STM['.$stm_name.'|'.$this->prepare_cursor[
 							$_data = '';
 						// write data into sql string
 						if (strstr($table_data[$field]['type'], 'int'))
-							$q_sub_data .= (is_numeric($_data) && isset($_data)) ? $_data : ($has_default ? $has_default : 'NULL');
+							$q_sub_data .= (is_numeric($_data) && isset($_data)) ? $_data : 'NULL';
 						else
-							$q_sub_data .= ($_data ? "'".$this->db_escape_string($_data)."'" : (($primary_key['value'] && $is_bool) ? "'".$this->db_boolean($_data, true)."'" : ($has_default ? "'".$this->db_escape_string($has_default)."'" : 'NULL')));
+							// if bool -> set bool, else write data
+							$q_sub_data .= $_data ? "'".($is_bool ? $this->db_boolean($_data, true) : $this->db_escape_string($_data))."'" : 'NULL';
 					}
 				}
 			}