diff --git a/dibi/dibi.php b/dibi/dibi.php
index 317c0610..92b8da8d 100644
--- a/dibi/dibi.php
+++ b/dibi/dibi.php
@@ -42,6 +42,7 @@ require_once __FILE__ . '/../libs/DibiResult.php';
 require_once __FILE__ . '/../libs/DibiResultIterator.php';
 require_once __FILE__ . '/../libs/DibiTranslator.php';
 require_once __FILE__ . '/../libs/DibiLogger.php';
+require_once __FILE__ . '/../libs/DibiVariable.php';
 
 
 
diff --git a/dibi/drivers/mssql.php b/dibi/drivers/mssql.php
index 0b32cb7b..af7cc1e3 100644
--- a/dibi/drivers/mssql.php
+++ b/dibi/drivers/mssql.php
@@ -265,6 +265,7 @@ class DibiMsSqlDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         mssql_free_result($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/drivers/mysql.php b/dibi/drivers/mysql.php
index 1be9137a..47231226 100644
--- a/dibi/drivers/mysql.php
+++ b/dibi/drivers/mysql.php
@@ -310,6 +310,7 @@ class DibiMySqlDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         mysql_free_result($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/drivers/mysqli.php b/dibi/drivers/mysqli.php
index 783bf6aa..c2d98bb5 100644
--- a/dibi/drivers/mysqli.php
+++ b/dibi/drivers/mysqli.php
@@ -297,6 +297,7 @@ class DibiMySqliDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         mysqli_free_result($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/drivers/odbc.php b/dibi/drivers/odbc.php
index 5aaab5d3..d4ee8e47 100644
--- a/dibi/drivers/odbc.php
+++ b/dibi/drivers/odbc.php
@@ -279,6 +279,7 @@ class DibiOdbcDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         odbc_free_result($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/drivers/oracle.php b/dibi/drivers/oracle.php
index 9b24c1a2..357bd08d 100644
--- a/dibi/drivers/oracle.php
+++ b/dibi/drivers/oracle.php
@@ -272,6 +272,7 @@ class DibiOracleDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         oci_free_statement($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/drivers/postgre.php b/dibi/drivers/postgre.php
index ef4dfa92..82a06739 100644
--- a/dibi/drivers/postgre.php
+++ b/dibi/drivers/postgre.php
@@ -140,14 +140,14 @@ class DibiPostgreDriver extends NObject implements DibiDriverInterface
     {
         if ($sequence === NULL) {
             // PostgreSQL 8.1 is needed
-            $res = $this->query("SELECT LASTVAL() AS seq");
+            $has = $this->query("SELECT LASTVAL() AS seq");
         } else {
-            $res = $this->query("SELECT CURRVAL('$sequence') AS seq");
+            $has = $this->query("SELECT CURRVAL('$sequence') AS seq");
         }
 
-        if (is_resource($res)) {
-            $row = pg_fetch_assoc($res);
-            pg_free_result($res);
+        if ($has) {
+            $row = $this->fetch();
+            $this->free();
             return $row['seq'];
         }
 
@@ -277,6 +277,7 @@ class DibiPostgreDriver extends NObject implements DibiDriverInterface
     public function free()
     {
         pg_free_result($this->resultset);
+        $this->resultset = NULL;
     }
 
 
diff --git a/dibi/libs/DibiDriverInterface.php b/dibi/libs/DibiDriverInterface.php
index 0c0e284f..2ef33559 100644
--- a/dibi/libs/DibiDriverInterface.php
+++ b/dibi/libs/DibiDriverInterface.php
@@ -191,23 +191,3 @@ interface DibiDriverInterface
     function getDibiReflection();
 
 }
-
-
-
-
-
-/**
- * Interface for user variable, used for generating SQL
- * @package dibi
- */
-interface DibiVariableInterface
-{
-    /**
-     * Format for SQL
-     *
-     * @param  object  destination DibiDriverInterface
-     * @param  string  optional modifier
-     * @return string  SQL code
-     */
-    public function toSql(DibiDriverInterface $driver, $modifier);
-}
diff --git a/dibi/libs/DibiVariable.php b/dibi/libs/DibiVariable.php
new file mode 100644
index 00000000..4f02f7bb
--- /dev/null
+++ b/dibi/libs/DibiVariable.php
@@ -0,0 +1,63 @@
+<?php
+
+/**
+ * dibi - tiny'n'smart database abstraction layer
+ * ----------------------------------------------
+ *
+ * Copyright (c) 2005, 2007 David Grudl aka -dgx- (http://www.dgx.cz)
+ *
+ * This source file is subject to the "dibi license" that is bundled
+ * with this package in the file license.txt.
+ *
+ * For more information please see http://php7.org/dibi/
+ *
+ * @copyright  Copyright (c) 2005, 2007 David Grudl
+ * @license    http://php7.org/dibi/license  dibi license
+ * @link       http://php7.org/dibi/
+ * @package    dibi
+ */
+
+
+
+/**
+ * Interface for user variable, used for generating SQL
+ * @package dibi
+ */
+interface DibiVariableInterface
+{
+    /**
+     * Format for SQL
+     *
+     * @param  object  destination DibiDriverInterface
+     * @param  string  optional modifier
+     * @return string  SQL code
+     */
+    public function toSql(DibiDriverInterface $driver, $modifier);
+}
+
+
+
+
+
+class DibiVariable extends NObject implements DibiVariableInterface
+{
+    /** @var mixed */
+    public $value;
+
+    /** @var string */
+    public $type;
+
+
+    public function __construct($value, $type)
+    {
+        $this->value = $value;
+        $this->type = $type;
+    }
+
+
+    public function toSql(DibiDriverInterface $driver, $modifier)
+    {
+        return $driver->format($this->value, $this->type);
+    }
+
+}
\ No newline at end of file