mysqli::debug

[edit] Last updated: Fri, 25 May 2012

mysqli::__construct

mysqli_connect

(PHP 5)

mysqli::__construct -- mysqli_connect — Open a new connection to the MySQL server

Описание

Объектно-ориентированный стиль

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") ]]]]]] )

Процедурный стиль

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.

Список параметров

host

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.

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.

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.

Возвращаемые значения

Returns an object which represents the connection to a MySQL Server.

Список изменений

Версия	Описание
5.3.0	Added the ability of persistent connections.

Примеры

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

Примечания

Замечание:
MySQLnd всегда подразумевает кодировку, которую использует по умолчанию сервер. Эта кодировка передается во время установки соединения/авторизации, которе использует 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.

Смотрите также

mysqli_real_connect() - Opens a connection to a mysql server
mysqli_options() - Set options
mysqli_connect_errno() - Возвращает код ошибки последней попытки соединения
mysqli_connect_error() - Возвращает описание последней ошибки подключения
mysqli_close() - Closes a previously opened database connection

mysqli::debug

mysqli::$connect_error

[edit] Last updated: Fri, 25 May 2012

add a note User Contributed Notes mysqli::__construct

boukeversteegh at gmail dot com 18-Apr-2011 06:19


(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;

?>

Anonymous 13-Sep-2009 05:37


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 25-Sep-2008 10:14


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.

chip1977 at mail dot ru 28-Jan-2008 04:52


To specify charset in my.cnf file you just have to add 

skip-character-set-client-handshake directive after 

[mysqld]

default-character-set=utf8

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