Note with Francis' example, using the function name link() will throw an error at runtime as it is already a function within the language. see: http://php.net/manual/en/function.link.php
mysqli::close
mysqli_close
(PHP 5, PHP 7)
mysqli::close -- mysqli_close — Closes a previously opened database connection
Description
Object oriented style
mysqli::close
( void
) : bool
Procedural style
Closes a previously opened database connection.
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 -
Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()
Return Values
Returns TRUE on success or FALSE on failure.
Examples
See mysqli_connect().
Notes
Note:
mysqli_close() will not close persistent connections. For additional details, see the manual page on persistent connections.
See Also
- mysqli::__construct() - Open a new connection to the MySQL server
- mysqli_init() - Initializes MySQLi and returns a resource for use with mysqli_real_connect()
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_free_result() - Frees the memory associated with a result
add a note
User Contributed Notes 3 notes
PD ¶
8 months ago
Francois ¶
1 year ago
Since a lot of manual examples recommend to use a variable to initiate your connection, it is interesting to know that mysqli_close() will unset that variable, causing further connection attempts to fail.
ex:
$link = mysqli_connect($host, $user, $pw);
if ($link) {
// Database is reachable
mysqli_close($link);
}
if ($link) {
// Database unreachable because $link = NULL
}
Easiest solution for me is to initiate connection through a function.
ex:
function link() {
global $host;
global $user;
global $pw;
global $link;
$link = mysqli_connect($host, $user, $pw);
}
link();
// Database is reachable
mysqli_close($link)
link();
// Database is reachable
mysqli_close($link)
php at dafydd dot com ¶
10 years ago
I've had situations where database connections appeared to persist following php execution. So, now, my __destructor function explicitly contains a $cxn->close(). It hurts nothing, and helps avoid memory leaks.
