mysqli::$connect_error
(php 5.3.3)
If $port is a string, such as "3306", mysqli::query() will not work, even though mysqli_connect_errno() reports no error (value 0)!
<?php
$mysqli = new mysqli("localhost", "user","password","database", "3306"); //port is a string!
$mysqli->query("SELECT 1;")->fetch_assoc();
// Fatal error: Call to a member function fetch_assoc() on a non-object
?>
This is particularly strange, since mysqli::query() should return a result object, or a boolean.
So, be careful when you read your port from a string or config file. Cast it to int first:
<?php
$port = (int)$port;
?>
mysqli::__construct
mysqli_connect
(PHP 5)
mysqli::__construct -- mysqli_connect — Open a new connection to the MySQL server
Description
Object oriented style
mysqli::__construct()
([ string
$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] )Procedural style
mysqli mysqli_connect
([ string
$host = ini_get("mysqli.default_host")
[, string $username = ini_get("mysqli.default_user")
[, string $passwd = ini_get("mysqli.default_pw")
[, string $dbname = ""
[, int $port = ini_get("mysqli.default_port")
[, string $socket = ini_get("mysqli.default_socket")
]]]]]] )Opens a connection to the MySQL Server running on.
Parameters
-
host -
Can be either a host name or an IP address. Passing the
NULLvalue or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol.Prepending host by p: opens a persistent connection. mysqli_change_user() is automatically called on connections opened from the connection pool.
-
username -
The MySQL user name.
-
passwd -
If not provided or
NULL, the MySQL server will attempt to authenticate the user against those user records which have no password only. This allows one username to be used with different permissions (depending on if a password as provided or not). -
dbname -
If provided will specify the default database to be used when performing queries.
-
port -
Specifies the port number to attempt to connect to the MySQL server.
-
socket -
Specifies the socket or named pipe that should be used.
Note:
Specifying the
socketparameter will not explicitly determine the type of connection to be used when connecting to the MySQL server. How the connection is made to the MySQL database is determined by thehostparameter.
Return Values
Returns an object which represents the connection to a MySQL Server.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | Added the ability of persistent connections. |
Examples
Example #1 mysqli::__construct() example
Object oriented style
<?php
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
/*
* This is the "official" OO way to do it,
* BUT $connect_error was broken until PHP 5.2.9 and 5.3.0.
*/
if ($mysqli->connect_error) {
die('Connect Error (' . $mysqli->connect_errno . ') '
. $mysqli->connect_error);
}
/*
* Use this instead of $connect_error if you need to ensure
* compatibility with PHP versions prior to 5.2.9 and 5.3.0.
*/
if (mysqli_connect_error()) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . $mysqli->host_info . "\n";
$mysqli->close();
?>
Object oriented style when extending mysqli class
<?php
class foo_mysqli extends mysqli {
public function __construct($host, $user, $pass, $db) {
parent::__construct($host, $user, $pass, $db);
if (mysqli_connect_error()) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
}
}
$db = new foo_mysqli('localhost', 'my_user', 'my_password', 'my_db');
echo 'Success... ' . $db->host_info . "\n";
$db->close();
?>
Procedural style
<?php
$link = mysqli_connect('localhost', 'my_user', 'my_password', 'my_db');
if (!$link) {
die('Connect Error (' . mysqli_connect_errno() . ') '
. mysqli_connect_error());
}
echo 'Success... ' . mysqli_get_host_info($link) . "\n";
mysqli_close($link);
?>
The above examples will output:
Success... MySQL host info: localhost via TCP/IP
Notes
Note:
MySQLnd always assumes the server default charset. This charset is sent during connection hand-shake/authentication, which mysqlnd will use.
Libmysqlclient uses the default charset set in the my.cnf or by an explicit call to mysqli_options() prior to calling mysqli_real_connect(), but after mysqli_init().
Note:
OO syntax only: If a connection fails an object is still returned. To check if the connection failed then use either the mysqli_connect_error() function or the mysqli->connect_error property as in the preceding examples.
Note:
If it is necessary to set options, such as the connection timeout, mysqli_real_connect() must be used instead.
Note:
Calling the constructor with no parameters is the same as calling mysqli_init().
Note:
Error "Can't create TCP/IP socket (10106)" usually means that the variables_order configure directive doesn't contain character E. On Windows, if the environment is not copied the SYSTEMROOT environment variable won't be available and PHP will have problems loading Winsock.
See Also
- mysqli_real_connect() - Opens a connection to a mysql server
- mysqli_options() - Set options
- mysqli_connect_errno() - Returns the error code from last connect call
- mysqli_connect_error() - Returns a string description of the last connect error
- mysqli_close() - Closes a previously opened database connection
add a note
User Contributed Notes
mysqli::__construct - [6 notes]
boukeversteegh at gmail dot com ¶
2 years ago
Anonymous ¶
3 years ago
If you get an error like
Can't connect to MySQL server on 'localhost' (10061)
and you use named pipes/socket connections (or aren't sure how you installed the MySQL server) try the following connect command:
<?php
mysqli_connect('.', $user_name, $password, $database_name, null, 'mysql');
?>
The '.' as hostname is absolutely necessary when using named pipes. 'localhost' won't work. 'mysql' is the standard name for the pipe/socket.
Slavyansk2.ru ¶
4 years ago
If you have error like "Trying to clone an uncloneable object of class..." when trying connect, add record
php_value zend.ze1_compatibility_mode 0
in your .htaccess file. This resolve connection problem.
paul at mtnlist dot com ¶
1 month ago
If you want to connect via an alternate port (other than 3306), as you might when using an ssh tunnel to another host, using "localhost" as the hostname will not work.
Using 127.0.0.1 will work. Apparently, if you specify the host as "localhost", the constructor ignores the port specified as an argument to the constructor.
oleg at mastak dot fi ¶
2 months ago
If you want to connect to local named pipe on windows and you get error "php_network_getaddresses: getaddrinfo failed: No such host is known. ", even if you using using "." as host, please check your if you are using mysqlnd driver: If this is true, then probably you need to update to version 5.4 of php:
Named pipes support for Windows was added in PHP version 5.4.0.
@ http://php.net/manual/en/mysqlnd.overview.php
Hopefully that will save you some time.
chip1977 at mail dot ru ¶
5 years ago
To specify charset in my.cnf file you just have to add
skip-character-set-client-handshake directive after
[mysqld]
default-character-set=utf8