PHP: dbmnextkey

Description

string dbmnextkey ( resource dbm_identifier, string key )

Returns the next key after key. By calling dbmfirstkey() followed by successive calls to dbmnextkey() it is possible to visit every key/value pair in the dbm database. For example:
Пример 1. Visiting every key/value pair in a DBM database

<?php $key = dbmfirstkey($dbm_id); while ($key) { echo "$key = " . dbmfetch($dbm_id, $key) . "\n"; $key = dbmnextkey($dbm_id, $key); } ?>

dbmnextkey

fischer at schlund dot de
19-Mar-2001 10:08


When you have a key "0" or so in your DB, then the example don't works, because "while ($key)" will return false for 0 ...


I had good experiences with "while (strlen($key)>0)" as condition ... because when we have the last key false is returned and false evaluates to "nothing" ...

fred at ontosys dot com
12-Oct-2000 10:41


dbmnext() seems to lose the thread if the program deletes keys as it walks through all rows.  I imagine that something similar happens with inserts.  One way around this is to make two passes:  one to collect the keys and one to manipulate the rows.  For example:





$old_keys = array();


for ($key = dbmfirstkey($db); $key; $key = dbmnextkey($db, $key)) {


  $old_keys[] = $key;


}


while (list($_, $key) = each($old_keys)) {


    dbmdelete($db, $key);


}

hiongun at kt dot co dot kr
08-Oct-1999 07:52


$key = dbmnextkey($dbm_id, $key) returns


"" on the second call.

karutla at hotmail dot com
01-Oct-1999 04:14


$key = dbmfirstkey($dbm_id);


while ($key) {


    dbmreplace($dbm_id, $value);


    $key = dbmnextkey($dbm_id, $key);


}





doesn't seem to iterate through all the records properly.