bindValue meaning code example

Example: bindvalue

<?php
/* Execute a prepared statement by binding PHP variables */
$calories = 150;
$colour = 'red';
$sth = $dbh->prepare('SELECT name, colour, calories
    FROM fruit
    WHERE calories < :calories AND colour = :colour');
$sth->bindValue(':calories', $calories, PDO::PARAM_INT);
$sth->bindValue(':colour', $colour, PDO::PARAM_STR);
$sth->execute();
?>