php教程

dba_exists

(PHP 4, PHP 5, PHP 7)

dba_existsCheck whether key exists

说明

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

dba_exists() checks whether the specified key exists 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

User Contributed Notes

frenzy dot ivan at gmail dot com 26-Nov-2008 05:37
<?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);

?>

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