What are the drawbacks of accessing the database multiple times in a loop, as demonstrated in the provided PHP code snippet?

Accessing the database multiple times in a loop can be inefficient and slow down the performance of your application. This is because each database query involves overhead in establishing a connection, executing the query, and fetching the results. To solve this issue, you can optimize your code by fetching all the necessary data in a single query outside of the loop and then iterating over the results in the loop.

// Fetch all necessary data outside of the loop
$query = "SELECT * FROM users";
$result = mysqli_query($connection, $query);

// Check if the query was successful
if ($result) {
    // Iterate over the results in the loop
    while ($row = mysqli_fetch_assoc($result)) {
        // Process each row of data
        echo $row['username'] . "<br>";
    }
} else {
    echo "Error: " . mysqli_error($connection);
}