What does the meaning of colon mark in this mysql statement?

PHP
1

Hello! According to the following code,what does the meaning of colon mark in this statement:
“INSERT INTO users (username, password) VALUES ( :username, : password )”;
code:

 $username = $_POST["username"];
$password = $_POST["password"];
 
// create connection to database
// ...
 
// sanitize the inputs
// ...
 
// create an MD5 hash of the password
$password = md5($password);
 
// save the values to the database
$sql = "INSERT INTO users (username, password) VALUES (:username, :password)";
 
$stmt = $db->prepare($sql);
 
$stmt->execute(array(
    ":username" => $username,
    ":password" => $password
));
2

That is not a MySQL statement but a PDO one.

The :username is a placeholder? and when the query is run it is replaced by the value in “:username” => $username,

You should be converting all your MySQL code to pdo or Mysqli now as MySQL is being depreciated.

3

It is worth noting that the colon is optional in your array keys so this will also work:


$stmt->execute(array(
    "username" => $username,
    "password" => $password
));