php dba函数实例

相关的函数

如下：

dba_close—关闭dba数据库

dba_delete—删除数据库中指定的key

dba_exists— 检查key是否存在

dba_fetch— 取得指定key的值

dba_firstkey— 获取第一个key

dba_handlers—列出所有可用的handler

dba_insert— 插入一条记录

dba_key_split— Splits a key in string representation into array representation

dba_list— 列出所有打开的数据库

dba_nextkey— 获取下一个key

dba_open—打开数据库

dba_optimize— 优化数据库

dba_popen— 使用长链接打开数据库

dba_replace—替换或者插入一条记录

dba_sync— 数据库同步

使用实例

1、跟踪用户和密码

$user = $_SERVER['argv'][1];

$password = $_SERVER['argv'][2];

$data_file = '/tmp/users.db';

$dbh = dba_open($data_file,'c','gdbm') or die("Can't open db $data_file");

if (dba_exists($user,$dbh)) {

print "User $user exists. Changing password.";

} else {

print "Adding user $user.";

}

dba_replace($user,$password,$dbh) or die("Can't write to database $data_file");

dba_close($dbh);

?>

2、对数据排序

$dbh = dba_open('users.db','gdbm') or die($php_errormsg);

if ($exists = dba_exists($_POST['username'],$dbh)) {

$serialized_data = dba_fetch($_POST['username'],$dbh) or die($php_errormsg);

$data = unserialize($serialized_data);

} else {

$data = array();

}

if ($_POST['new_password']) {

$data['password'] = $_POST['new_password'];

}

$data['last_access'] = time();

if ($exists) {

dba_replace($_POST['username'],serialize($data),$dbh);

} else {

dba_insert($_POST['username'],$dbh);

}

dba_close($dbh);

?>

3、计算所有密码的总长度

$data_file = '/tmp/users.db';

$total_length = 0;

if (! ($dbh = dba_open($data_file,'r','gdbm'))) {

die("Can't open database $data_file");

}

$k = dba_firstkey($dbh);

while ($k) {

$total_length += strlen(dba_fetch($k,$dbh));

$k = dba_nextkey($dbh);

}

print "Total length of all passwords is $total_length characters.";

dba_close($dbh);

?>

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