diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 543d5cc..00294c3 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -2534,7 +2534,7 @@
 	 *
 	 * Determines if a string represents a literal value or a field name
 	 *
-	 * @param	string
+	 * @param	string	$str
 	 * @return	bool
 	 */
 	protected function _is_literal($str)
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 4516521..41b50f0 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -353,6 +353,24 @@
 		return $this;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Is literal
+	 *
+	 * Determines if a string represents a literal value or a field name
+	 *
+	 * @param	string	$str
+	 * @return	bool
+	 */
+	protected function _is_literal($str)
+	{
+		$str = trim($str);
+
+		return (empty($str) OR ctype_digit($str) OR $str[0] === "'" OR in_array($str, array('TRUE', 'FALSE'), TRUE));
+	}
+
+
 }
 
 /* End of file pdo_pgsql_driver.php */
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index a52777b..c2bc4d9 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -674,6 +674,23 @@
 	// --------------------------------------------------------------------
 
 	/**
+	 * Is literal
+	 *
+	 * Determines if a string represents a literal value or a field name
+	 *
+	 * @param	string	$str
+	 * @return	bool
+	 */
+	protected function _is_literal($str)
+	{
+		$str = trim($str);
+
+		return (empty($str) OR ctype_digit($str) OR $str[0] === "'" OR in_array($str, array('TRUE', 'FALSE'), TRUE));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void