Here are the similarities and differences I noticed when switching from the mysql_ prefixed functions to the mysqli_ functions in PHP.
Creating a Connection
Creating and closing a connection are exactly the same using mysqli_:
// Creating a Connection with mysql_connect() $conn = mysql_connect($servername, $username, $password); // Do stuff with database here. // Close the Connection mysql_close($conn); //////////////////////////////////// // Creating a Connection with mysqli_connect() $conn = mysqli_connect($servername, $username, $password); // Do stuff with database here. // Close the Connection mysqli_close($conn);
Connecting to a Database
Connecting to a database can actually be done with one less step with mysqli_:
// Connecting to a Database with mysql_connect() and mysql_select_db() $conn = mysql_connect($servername, $username, $password); $db = mysql_select_db($database, $conn); // Do stuff with database here. // Close the Connection mysql_close($conn); //////////////////////////////////// // Connecting to a Database with mysqli_connect() $conn = mysqli_connect($servername, $username, $password, $database); // Do stuff with database here. // Close the Connection mysqli_close($conn);
Getting a Single Value With mysqli_
// Connecting to a Database with mysqli_connect()
$conn = mysqli_connect($servername, $username, $password, $database);
// Getting a Single Value Using mysqli_fetch_array and mysqli_query
$user_id = mysqli_fetch_array(mysqli_query($conn, "SELECT `user_id` FROM `user_ids` WHERE `user_email` = 'user-email@example.com';"));
if ( ($user_id[0] !== '') && !(empty($user_id[0])) ) {
$user_id = $user_id[0];
} else {
return "Error selecting user.";
}
// Close the Connection
mysqli_close($conn);
Please Note: To keep the post simple, I left out error reporting. If you are interacting with a database, it is important to include a fallback for if a connection fails or a database cannot be connected to using a function like this: die( ‘Could not connect to mysqli: ‘ . mysqli_error() );