dba_exists()

(PHP 4, PHP 5, PHP 7)

Check whether key exists

说明

dba_exists(string $key,resource $handle): bool

dba_exists() checks whether the specified$keyexists in the database.

参数

$key

The key the check is performed for.

$handle

The database handler, returned by dba_open() or dba_popen().

返回值

Returns TRUE if the key exists,FALSE otherwise.

参见

• dba_delete()Delete DBA entry specified by key
• dba_fetch()Fetch data specified by key
• dba_insert()Insert entry
• dba_replace()Replace or insert entry

<?php
$index = 4;
$id = dba_open("frenzy.db", "w", "flatfile");
if(!$id) exit ("Some error...");
if(dba_exists($index, $id)) exit ("This key is using");
dba_close($id);
?>