# construct

mysqli::\_\_construct

mysqli::connect

mysqli_connect

Open a new connection to the MySQL server

# 

ENTITY

ENTITY

<div data-wrapper="1" role="mysqli">

public

</div>

<div data-wrapper="1" role="mysqli">

mysqli::\_\_construct

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

hostname

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

username

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="attribute">

\#\[\SensitiveParameter\]

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

password

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

database

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

int

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

port

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

socket

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

public

</div>

<div data-wrapper="1" role="mysqli">

bool

</div>

<div data-wrapper="1" role="mysqli">

mysqli::connect

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

hostname

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

username

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="attribute">

\#\[\SensitiveParameter\]

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

password

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

database

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

int

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

port

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

<div data-wrapper="1" role="mysqli">

string

</div>

<div data-wrapper="1" role="mysqli">

null

</div>

<div data-wrapper="1" role="mysqli">

socket

</div>

<div data-wrapper="1" role="mysqli">

ENTITY

</div>

ENTITY

mysqli

false

mysqli_connect

string

null

hostname

ENTITY

string

null

username

ENTITY

<div data-wrapper="1" role="attribute">

\#\[\SensitiveParameter\]

</div>

string

null

password

ENTITY

string

null

database

ENTITY

int

null

port

ENTITY

string

null

socket

ENTITY

Opens a connection to the MySQL Server.

# 

ENTITY

`hostname`  
Can be either a host name or an IP address. When passing ENTITY, the value is retrieved from [mysqli.default_host](#ini.mysqli.default-host). When possible, pipes will be used instead of the TCP/IP protocol. The TCP/IP protocol is used if a host name and port number are provided together e.g. `localhost:3308`.

Prepending host by `p:` opens a persistent connection. `mysqli_change_user` is automatically called on connections opened from the connection pool.

`username`  
The MySQL username or ENTITY to assume the username based on the [mysqli.default_user](#ini.mysqli.default-user) ini option.

`password`  
The MySQL password or ENTITY to assume the password based on the [mysqli.default_pw](#ini.mysqli.default-pw) ini option.

`database`  
The default database to be used when performing queries or ENTITY.

`port`  
The port number to attempt to connect to the MySQL server or ENTITY to assume the port based on the [mysqli.default_port](#ini.mysqli.default-port) ini option.

`socket`  
The socket or named pipe that should be used or ENTITY to assume the socket based on the [mysqli.default_socket](#ini.mysqli.default-socket) ini option.

> [!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 `hostname` parameter.

# 

ENTITY

mysqli::\_\_construct always returns an object which represents the connection to a MySQL Server, regardless of it being successful or not.

`mysqli_connect` returns an object which represents the connection to a MySQL Server, ENTITY.

mysqli::connect returns ENTITY on successENTITY. Prior to PHP 8.1.0, returns ENTITY on success.

# 

ENTITY ENTITY

As of PHP 8.5.0, calling the constructor on an already-constructed object throws an Error.

# 

ENTITY

| ENTITY | ENTITY |
|----|----|
| 8.5.0 | Calling the constructor on an already-constructed object now throws an Error. |
| 8.1.0 | mysqli::connect now returns ENTITY instead of ENTITY on success. |
| 7.4.0 | All parameters are now nullable. |

# 

ENTITY

<div class="example">

<div class="title">

mysqli::\_\_construct example

</div>

ENTITY

```
<?php

/* You should enable error reporting for mysqli before attempting to make a connection */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');

/* Set the desired charset after establishing a connection */
$mysqli->set_charset('utf8mb4');

printf("Success... %s\n", $mysqli->host_info);

   
```

ENTITY

```
<?php

/* You should enable error reporting for mysqli before attempting to make a connection */
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);

$mysqli = mysqli_connect('localhost', 'my_user', 'my_password', 'my_db');

/* Set the desired charset after establishing a connection */
mysqli_set_charset($mysqli, 'utf8mb4');

printf("Success... %s\n", mysqli_get_host_info($mysqli));

   
```

ENTITY

    Success... localhost via TCP/IP

       

</div>

<div class="example">

<div class="title">

Extending mysqli class

</div>

```
<?php

class FooMysqli extends mysqli {
    public function __construct($host, $user, $pass, $db, $port, $socket, $charset) {
        mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
        parent::__construct($host, $user, $pass, $db, $port, $socket);
        $this->set_charset($charset);
    }
}

$db = new FooMysqli('localhost', 'my_user', 'my_password', 'my_db', 3306, null, 'utf8mb4');

   
```

</div>

<div class="example">

<div class="title">

Manual error handling

</div>

If error reporting is disabled, the developer is responsible for checking and handling failures

ENTITY

```
<?php

error_reporting(0);
mysqli_report(MYSQLI_REPORT_OFF);
$mysqli = new mysqli('localhost', 'my_user', 'my_password', 'my_db');
if ($mysqli->connect_errno) {
    throw new RuntimeException('mysqli connection error: ' . $mysqli->connect_error);
}

/* Set the desired charset after establishing a connection */
$mysqli->set_charset('utf8mb4');
if ($mysqli->errno) {
    throw new RuntimeException('mysqli error: ' . $mysqli->error);
}

   
```

ENTITY

```
<?php

error_reporting(0);
mysqli_report(MYSQLI_REPORT_OFF);
$mysqli = mysqli_connect('localhost', 'my_user', 'my_password', 'my_db');
if (mysqli_connect_errno()) {
    throw new RuntimeException('mysqli connection error: ' . mysqli_connect_error());
}

/* Set the desired charset after establishing a connection */
mysqli_set_charset($mysqli, 'utf8mb4');
if (mysqli_errno($mysqli)) {
    throw new RuntimeException('mysqli error: ' . mysqli_error($mysqli));
}

   
```

</div>

# 

ENTITY ENTITY

> [!NOTE]
> ENTITY only: If the connection fails, an object is still returned. To check whether the connection failed, use either the `mysqli_connect_error` function or the [mysqli-ENTITYconnect_error](#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](#ini.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.

# 

ENTITY

`mysqli_real_connect`, `mysqli_options`, `mysqli_connect_errno`, `mysqli_connect_error`, `mysqli_close`