How can PHP beginners ensure that only one value is set to '1' in a specific column of a MySQL table?

To ensure that only one value is set to '1' in a specific column of a MySQL table, PHP beginners can achieve this by first updating all values in the column to '0' before setting the desired value to '1'. This way, only one row will have the value '1' at any given time. 

<?php
// Connect to MySQL database
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";
$conn = new mysqli($servername, $username, $password, $dbname);

// Update all values in the column to '0'
$sql_update = "UPDATE table_name SET column_name = '0'";
$conn->query($sql_update);

// Set the desired value to '1'
$id = 1; // ID of the row to set to '1'
$sql_set = "UPDATE table_name SET column_name = '1' WHERE id = $id";
$conn->query($sql_set);

// Close database connection
$conn->close();
?>

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