Index: trunk/core/kernel/db/dbitem.php
===================================================================
diff -u -r2711 -r2787
--- trunk/core/kernel/db/dbitem.php	(.../dbitem.php)	(revision 2711)
+++ trunk/core/kernel/db/dbitem.php	(.../dbitem.php)	(revision 2787)
@@ -388,6 +388,7 @@
 			$res = $res && $this->ValidateRange($field, $params);
 			$res = $res && $this->ValidateUnique($field, $params);
 			$res = $res && $this->ValidateRequired($field, $params);
+			$res = $res && $this->CustomValidation($field, $params);
 			
 			// If Formatter has set some error messages during values parsing 
 			$error_field = isset($params['error_field']) ? $params['error_field'] : $field;
@@ -410,6 +411,18 @@
 		return $global_res;
 	}	
 	
+	/**
+	 * Check field value by user-defined alghoritm
+	 *
+	 * @param string $field field name
+	 * @param Array $params field options from config
+	 * @return bool
+	 */
+	function CustomValidation($field, $params)
+	{
+		return true;
+	}
+	
 	function HasErrors()
 	{
 		$global_res = false;