PHPでcdbファイル読み込み

$cdbid = dba_open("test.cdb", "r", "cdb");

$key = dba_firstkey ( $cdbid );
$cols[] = dba_fetch($key,$cdbid);
while($key = dba_nextkey ( $cdbid )){
$cols[] = dba_fetch($key,$cdbid);
}
print_r($cols);
?>