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mysql_connect

(PHP 3, PHP 4, PHP 5)

mysql_connect -- Open a connection to a MySQL Server

Description

resource mysql_connect ( [string server [, string username [, string password [, bool new_link [, int client_flags]]]]] )

Opens or reuses a connection to a MySQL server.

Parameters

server

The MySQL server. It can also include a port number. e.g. "hostname:port" or a path to a local socket e.g. ":/path/to/socket" for the localhost.

If the PHP directive mysql.default_host is undefined (default), then the default value is 'localhost:3306'. In SQL safe mode, this parameter is ignored and value 'localhost:3306' is always used.

username

The username. Default value is defined by mysql.default_user. In SQL safe mode, this parameter is ignored and the name of the user that owns the server process is used.

password

The password. Default value is defined by mysql.default_password. In SQL safe mode, this parameter is ignored and empty password is used.

new_link

If a second call is made to mysql_connect() with the same arguments, no new link will be established, but instead, the link identifier of the already opened link will be returned. The new_link parameter modifies this behavior and makes mysql_connect() always open a new link, even if mysql_connect() was called before with the same parameters. In SQL safe mode, this parameter is ignored.

client_flags

The client_flags parameter can be a combination of the following constants: MYSQL_CLIENT_SSL, MYSQL_CLIENT_COMPRESS, MYSQL_CLIENT_IGNORE_SPACE or MYSQL_CLIENT_INTERACTIVE. Read the section about Table 2 for further information. In SQL safe mode, this parameter is ignored.

Return Values

Returns a MySQL link identifier on success, or FALSE on failure.

ChangeLog

VersionDescription
4.3.0 Added the client_flags parameter.
4.2.0 Added the new_link parameter.
3.0.10 Added support for ":/path/to/socket" with server.
3.0.0 Added support for ":port" with server.

Examples

Example 1. mysql_connect() example

<?php
$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Example 2. mysql_connect() example using hostname:port syntax

<?php
// we connect to example.com and port 3307
$link = mysql_connect('example.com:3307', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);

// we connect to localhost at port 3307
$link = mysql_connect('127.0.0.1:3307', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Example 3. mysql_connect() example using ":/path/to/socket" syntax

<?php
// we connect to localhost and socket e.g. /tmp/mysql.sock

//variant 1: ommit localhost
$link = mysql_connect('/tmp/mysql', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);


// variant 2: with localhost
$link = mysql_connect('localhost:/tmp/mysql.sock', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
mysql_close($link);
?>

Notes

Note: Whenever you specify "localhost" or "localhost:port" as server, the MySQL client library will override this and try to connect to a local socket (named pipe on Windows). If you want to use TCP/IP, use "127.0.0.1" instead of "localhost". If the MySQL client library tries to connect to the wrong local socket, you should set the correct path as mysql.default_host string in your PHP configuration and leave the server field blank.

Note: The link to the server will be closed as soon as the execution of the script ends, unless it's closed earlier by explicitly calling mysql_close().

Note: You can suppress the error message on failure by prepending a @ to the function name.

See Also

mysql_pconnect()
mysql_close()

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