How important is it to establish a database connection in PHP scripts that interact with databases, and what impact can it have on the overall functionality?

Establishing a database connection in PHP scripts that interact with databases is crucial for the scripts to successfully retrieve or store data. Without a proper connection, the scripts will not be able to communicate with the database, leading to errors or incomplete functionality. To establish a database connection in PHP, you can use the mysqli_connect() function to connect to a MySQL database.

// Database credentials
$servername = "localhost";
$username = "username";
$password = "password";
$database = "dbname";

// Create connection
$conn = mysqli_connect($servername, $username, $password, $database);

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
echo "Connected successfully";