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
public mysqli::close(): bool
Procedural style
Closes a previously opened database connection.
Open non-persistent MySQL connections and result sets are automatically closed when their objects are destroyed. Explicitly closing open connections and freeing result sets is optional. However, it's a good idea to close the connection as soon as the script finishes performing all of its database operations, if it still has a lot of processing to do after getting the results.
Parameters
-
mysql -
Procedural style only: A mysqli object returned by mysqli_connect() or mysqli_init()
Return Values
Returns true on success or false on failure.
Examples
Example #1 mysqli::close() example
Object oriented style
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
$result = $mysqli->query("SELECT Name, CountryCode FROM City ORDER BY ID LIMIT 3");
/* Close the connection as soon as it's no longer needed */
$mysqli->close();
foreach ($result as $row) {
/* Processing of the data retrieved from the database */
}
Procedural style
<?php
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");
$result = mysqli_query($mysqli, "SELECT Name, CountryCode FROM City ORDER BY ID LIMIT 3");
/* Close the connection as soon as it's no longer needed */
mysqli_close($mysqli);
foreach ($result as $row) {
/* Processing of the data retrieved from the database */
}
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 an object 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 ¶
5 years ago
Francois ¶
5 years 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 ¶
15 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.
