diff --git a/dblayer.php b/dblayer.php
index 7f69487..f6d3cdb 100644
--- a/dblayer.php
+++ b/dblayer.php
@@ -167,7 +167,7 @@ class dblayer extends PDO
   /** Return the connected database name from DSN used to connect */
   public function databasename ()
   {
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     $vals = explode (";", substr (strstr ($this->dsn, ":"), 1));
@@ -185,7 +185,7 @@ class dblayer extends PDO
   /** Return all the tables available in the database */
   public function listTables ()
   {
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     switch ($this->getAttribute(PDO::ATTR_DRIVER_NAME))
@@ -515,7 +515,7 @@ class dblayer extends PDO
   public function insert ($datas)
   {
     if ($this->debug) echo "== Entering insert\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     if ($this->unique === null)
@@ -605,7 +605,7 @@ class dblayer extends PDO
                         $whereOr=false)
   {
     if ($this->debug) echo "== Entering read\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     if ($select !== null && !is_array ($select))
@@ -721,7 +721,7 @@ class dblayer extends PDO
   public function update ($updatekey, $datas)
   {
     if ($this->debug) echo "== Entering update\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     if (count ($this->fields) === 0)
@@ -806,7 +806,7 @@ class dblayer extends PDO
   public function delete ($deletekey)
   {
     if ($this->debug) echo "== Entering delete\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"));
     $req = "DELETE FROM $this->sep$this->tableprefix$this->table$this->sep ";
     $req .= "WHERE $this->primary = :primary";
@@ -843,7 +843,7 @@ class dblayer extends PDO
   public function dropTable ()
   {
     if ($this->debug) echo "== Entering dropTables\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"));
     $sql = "DROP TABLE $this->sep$this->tableprefix$this->table$this->sep";
     if ($this->debug)
@@ -870,7 +870,7 @@ class dblayer extends PDO
   public function createTable ()
   {
     if ($this->debug) echo "== Entering createTable\n";
-    if ($this === null)
+    if ($this->sep === "")
       throw new Exception (dgettext("domframework", "Database not connected"),
                            500);
     if (count ($this->fields) === 0)