PHP syntax to establish database connection

Sure, here is a step-by-step guide on how to establish a database connection in PHP:

1. First, you need to open a new PHP tag:

<?php

2. Then, you need to define your database details as variables:

$servername = "localhost"; // replace with your server name
$username = "username"; // replace with your username
$password = "password"; // replace with your password
$dbname = "database"; // replace with your database name

3. After that, you can use these variables to establish a new connection using mysqli_connect() function:

$conn = mysqli_connect($servername, $username, $password, $dbname);

4. You should always check if the connection was successful. If mysqli_connect() returns false, mysqli_connect_error() will return the last error description:

if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

5. If the connection is successful, you can proceed with your database operations.

6. Don't forget to close the connection after you're done with your operations:

mysqli_close($conn);

7. Finally, close your PHP tag:

?>

So, the complete PHP code to establish a database connection would look like this:

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

// Check connection
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}
// proceed with your operations
// ...

// close the connection
mysqli_close($conn);
?>

Remember to replace the placeholders with your actual database details.