PHP Opens a connection to a mysql server

说明

面向对象风格

bool mysqli::real_connect ([ string $host [, string $username [, string $passwd [, string $dbname [, int $port [, string $socket [, int $flags ]]]]]]] )

过程化风格

bool mysqli_real_connect ( mysqli $link [, string $host [, string $username [, string $passwd [, string $dbname [, int $port [, string $socket [, int $flags ]]]]]]] )

Establish a connection to a MySQL database engine.

This function differs from mysqli_connect():

mysqli_real_connect() needs a valid object which has to be created by function mysqli_init().
With the mysqli_options() function you can set various options for connection.
There is a flags parameter.

参数

link

仅以过程化样式：由 mysqli_connect() 或 mysqli_init() 返回的链接标识。

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.

username

The MySQL user name.

passwd

If 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 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.

flags

With the parameter flags you can set different connection options:

**Supported flags**
Name	Description
`MYSQLI_CLIENT_COMPRESS`	Use compression protocol
`MYSQLI_CLIENT_FOUND_ROWS`	return number of matched rows, not the number of affected rows
`MYSQLI_CLIENT_IGNORE_SPACE`	Allow spaces after function names. Makes all function names reserved words.
`MYSQLI_CLIENT_INTERACTIVE`	Allow interactive_timeout seconds (instead of wait_timeout seconds) of inactivity before closing the connection
`MYSQLI_CLIENT_SSL`	Use SSL (encryption)

Note:
For security reasons the MULTI_STATEMENT flag is not supported in PHP. If you want to execute multiple queries use the mysqli_multi_query() function.

返回值

成功时返回 TRUE，或者在失败时返回 FALSE。

范例

Example #1 mysqli::real_connect() example

面向对象风格


<?php

$mysqli = mysqli_init();
if (!$mysqli) {
    die('mysqli_init failed');
}

if (!$mysqli->options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
    die('Setting MYSQLI_INIT_COMMAND failed');
}

if (!$mysqli->options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
    die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}

if (!$mysqli->real_connect('localhost', 'my_user', 'my_password', 'my_db')) {
    die('Connect Error (' . mysqli_connect_errno() . ') '
            . mysqli_connect_error());
}

echo 'Success... ' . $mysqli->host_info . "\n";

$mysqli->close();
?>

面向对象风格 when extending mysqli class


<?php

class foo_mysqli extends mysqli {
    public function __construct($host, $user, $pass, $db) {
        parent::init();

        if (!parent::options(MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
            die('Setting MYSQLI_INIT_COMMAND failed');
        }

        if (!parent::options(MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
            die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
        }

        if (!parent::real_connect($host, $user, $pass, $db)) {
            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();
?>

过程化风格


<?php

$link = mysqli_init();
if (!$link) {
    die('mysqli_init failed');
}

if (!mysqli_options($link, MYSQLI_INIT_COMMAND, 'SET AUTOCOMMIT = 0')) {
    die('Setting MYSQLI_INIT_COMMAND failed');
}

if (!mysqli_options($link, MYSQLI_OPT_CONNECT_TIMEOUT, 5)) {
    die('Setting MYSQLI_OPT_CONNECT_TIMEOUT failed');
}

if (!mysqli_real_connect($link, 'localhost', 'my_user', 'my_password', 'my_db')) {
    die('Connect Error (' . mysqli_connect_errno() . ') '
            . mysqli_connect_error());
}

echo 'Success... ' . mysqli_get_host_info($link) . "\n";

mysqli_close($link);
?>

以上例程会输出：

Success... MySQL host info: localhost via TCP/IP

注释

Note:
MySQLnd 总是使用服务器的默认字符集。此字符集在连接握手／认证时发送，并被 mysqlnd 使用。
Libmysqlclient 使用 my.cnf 中的默认字符集或者由在调用 mysqli_init() 之后， mysqli_real_connect() 之前先调用 mysqli_options() 来指定。

参见

mysqli_connect() - 别名 mysqli::__construct
mysqli_init() - Initializes MySQLi and returns a resource for use with mysqli_real_connect()
mysqli_options() - Set options
mysqli_ssl_set() - Used for establishing secure connections using SSL
mysqli_close() - 关闭先前打开的数据库连接

mysqli::real_connect

mysqli_real_connect

说明

参数

返回值

范例

注释

参见

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