(PHP 5)
mysqli::__construct -- mysqli_connect — Open a new connection to the MySQL server
Объектно-ориентированный стиль
Процедурный стиль
Opens a connection to the MySQL Server running on.
Can be either a host name or an IP address. Passing the NULL value 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.
The MySQL user name.
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).
If provided will specify the default database to be used when performing queries.
Specifies the port number to attempt to connect to the MySQL server.
Specifies the socket or named pipe that should be used.
Замечание:
Specifying the socket parameter 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 the host parameter.
Returns an object which represents the connection to a MySQL Server.
| Версия | Описание |
|---|---|
| 5.3.0 | Added the ability of persistent connections. |
Пример #1 mysqli::__construct() example
Объектно-ориентированный стиль
<?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";
$mysqli->close();
?>
Объектно-ориентированный стиль when extending mysqli class
<?php
class foo_mysqli extends mysqli {
public function __construct($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();
?>
Процедурный стиль
<?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);
?>
Результат выполнения данных примеров:
Success... MySQL host info: localhost via TCP/IP
Замечание:
MySQLnd всегда подразумевает кодировку, которую использует по умолчанию сервер. Эта кодировка посылается в течение установления соединения/авторизации, используемого mysqlnd.
Libmysql по умолчанию использует кодировку, установленную в my.cnf или специальным вызовом mysqli_options() до использования mysqli_real_connect(), но после mysqli_init().
Замечание:
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.
Замечание:
If it is necessary to set options, such as the connection timeout, mysqli_real_connect() must be used instead.
Замечание:
Calling the constructor with no parameters is the same as calling mysqli_init().
Замечание:
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.