mysqli_options()

The mysqli_options() function is used to set additional connection options and affect system behavior. This function must be called after mysqli_init() and before mysqli_real_connect().

EXAMPLE

<?php
// 1. Initialize an empty connection object
$connection = mysqli_init();

if (!$connection) {
    die("mysqli_init failed");
}

// 2. Set advanced options (Timeout to 10 seconds)
// NOTE: The mysqli_options() function can ONLY be called on an empty connection created with 
// mysqli_init(). The MYSQLI_OPT_CONNECT_TIMEOUT constant determines the maximum time in seconds 
// that PHP has to establish contact with the database server.
mysqli_options($connection, MYSQLI_OPT_CONNECT_TIMEOUT, 10);
echo "Connection timeout set to 10 seconds.<br>";

// 3. Establish the actual connection to the server using all configured options
mysqli_real_connect($connection, "localhost", "root", "", "mysqli_database");

mysqli_close($connection);
?>

RESULT

The result will be displayed here...

Let's look at some of the most important configuration parameters:

MYSQLI_OPT_CONNECT_TIMEOUT: sets the connection timeout in seconds.
MYSQLI_OPT_LOCAL_INFILE: enables or disables the use of LOAD LOCAL INFILE.
MYSQLI_INIT_COMMAND: command to be executed immediately after establishing the connection.
MYSQLI_READ_DEFAULT_FILE: read options from a specific file instead of my.cnf.
MYSQLI_READ_DEFAULT_GROUP: read from a specific group in the my.cnf file.
MYSQLI_SERVER_PUBLIC_KEY: RSA public key file for SHA-256 authentication.
MYSQLI_OPT_NET_CMD_BUFFER_SIZE: sets the command buffer size (mysqlnd).
MYSQLI_OPT_NET_READ_BUFFER_SIZE: read buffer size (mysqlnd).
MYSQLI_INT_AND_FLOAT_NATIVE: converts numeric columns into PHP numbers (mysqlnd only).
MYSQLI_OPT_SSL_VERIFY_SERVER_CERT: verification of the server SSL certificate (mysqlnd only).

Practical use: This function is crucial when working on projects where server connections can be slow or when you need additional security (e.g., SSL). By setting a connection timeout, you ensure that your website does not "hang" if the database is unreachable.

It is always called before establishing the actual connection.
It allows fine-tuning performance via the mysqlnd driver.
Indispensable for secure SSL communication between PHP and MySQL.