CascadiaPHP 2024

mysql_close

(PHP 4, PHP 5)

mysql_closeClose MySQL connection

Avviso

Questa enstensione deprecata da PHP 5.5.0, e sarà rimossa in futuro. Al suo posto, usare l'estensione MySQLi o PDO_MySQL. Vedere anche la guida MySQL: scelta dell'API e le FAQ relative per ulteriori informazioni. Le alternative a questa funzione includono:

Descrizione

mysql_close(resource $link_identifier = NULL): bool

mysql_close() closes the non-persistent connection to the MySQL server that's associated with the specified link identifier. If link_identifier isn't specified, the last opened link is used.

Open non-persistent MySQL connections and result sets are automatically destroyed when a PHP script finishes its execution. So, while explicitly closing open connections and freeing result sets is optional, doing so is recommended. This will immediately return resources to PHP and MySQL, which can improve performance. For related information, see freeing resources

Elenco dei parametri

link_identifier

La connessione MySQL. Se l'identificatore di collegamento non è fornito, si utilizza l'ultimo collegamento aperto da mysql_connect(). Se la connessione non viene trovata o se non può essere creata, viene gererato un errore di livello E_WARNING.

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Esempi

Example #1 mysql_close() example

<?php
$link
= mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!
$link) {
die(
'Could not connect: ' . mysql_error());
}
echo
'Connected successfully';
mysql_close($link);
?>

Il precedente esempio visualizzerà:

Connected successfully

Note

Nota:

mysql_close() will not close persistent links created by mysql_pconnect(). For additional details, see the manual page on persistent connections.

Vedere anche:

add a note

User Contributed Notes 4 notes

up
5
bbodelcampo at yahoo dot co dot uk
18 years ago
A little note about multiple simultaneous connections to different hosts...

I work on a site that pulls content primarily from one db but uses a db on a foreign server to verify licensing. One might expect the following to work:

<?php
// Open the connection to the primary db
$res1 = mysql_connect($host1, $user1, $pass1);
mysql_select_db($db1);

// Open connection to the license server
$res2 = mysql_connect($host2, $user2, $pass2);
mysql_select_db($db2, $res2);

// Pull license data and close when done
mysql_query($check_sql, $res2);
// ...
mysql_close($res2);

// Now pull content from the primary db
// Not specifying the resource should default to the last open db
mysql_query($query);
// ...
?>

Turns out this last query, since it cant find an active connection, will try to connect with mysql_connect() with no paramaters. But if instead you do it as mysql_query($query, $res1), or alternatively, run the mysql_connect for this host again then it works fine. Thus, it doesnt seem to be possible to have code with an overarching "global" db connection interspersed with temporary connections to another host/db....
up
-5
mdes[SPAM]saintes at gmail dot com
14 years ago
i just came over a problem that i had with apache.

It crashs and said :

"Parent: child process exited with status 3221225477 -- Restarting."

the error came from the extesion php_mysql.dll

i didn't understand what was the reason of that crash..

Then, i debug the script that i had downloaded and i noticed that that was the function mysql_close() which caused the problem.

The solution is, to send to it the link identifier which is optionnal in the description but cause a crash with no commentary.

Thanks to agneady.
up
-7
Anonymous
14 years ago
At least with PHP5.3.2 and Windows connecting by tcp, you should always use this mysql_close() function to close and free up the tcp socket being used by PHP. Garbage collection after script execution does not close the tcp socket on its own. The socket would otherwise remain in 'wait' state for approximately 30 seconds, and any additional page loads/connection attempts would only add to the total number of open tcp connections. This wait time does not appear to be configurable via PHP settings.
up
-9
omega99999 at gmail dot com
13 years ago
The variable is definitely not optional in 5.3... Caused me a bit of a headache when I was debugging until I realized it was the close function that was causing a hang. So if using just:

<?php
mysql_connect
(<...>);

mysql_close();
?>

Use:

<?php
$connection
= mysql_connect(<...>);

mysql_close($connection);
?>

(where $connection is any variable of your choice)
To Top