function db_existRecord($sField, $sValue, $sTable, $sWhere) {
	global $dbLink;
	$query  = "SELECT count(*) as nCount FROM ".$sTable;
	if($sWhere!="") {
		$query .= " WHERE ".$sWhere." AND ".$sField."='".$sValue."'";
	} else {
		$query .= " WHERE ".$sField."='".$sValue."'";
	}
	$result = mysql_query($query, $dbLink);
	$line = mysql_fetch_array($result, MYSQL_ASSOC);
	$retval = ($line["nCount"]>0 ? TRUE : FALSE);
	mysql_free_result($result);
	return $retval;
}