mysql_close

(PHP 4, PHP 5)

mysql_close — Close MySQL connection

Warning

This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide. Alternatives to this function include:

mysqli_close()
PDO: Assign the value of null to the PDO object

Description

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

Parameters

link_identifier: The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns true on success or false on failure.

Examples

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);
?>

The above example will output:

Connected successfully

Notes

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

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User Contributed Notes 2 notes

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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....