The object-oriented style compared to the procedural style

$result = $db->query($query); // oo
$result = mysqli_query($db, $query); // procedural
      
$error_message = $db->error; // oo
$error_message = mysqli_error($db); // procedural
      
$row = $result->fetch_assoc(); // oo
$row = mysqli_fetch_assoc($result); // procedural
      
$row_count = $result->num_rows; // oo
$row_count = mysqli_num_rows($result); // procedural
      
$count = $db->affected_rows; // oo
$count = mysqli_affected_rows($db); // procedural
      
$result->free(); // oo
$result->free(); mysqli_free_result($result); // procedural
      
$statement = $db->prepare($query); // oo      
$statement = mysqli_prepare($db, $query); // procedural
      
$statement->bind_param("i", $category_id); // oo    
mysqli_bind_param($statement, "i", $category_id); // procedural
      
$success = $statement->execute(); // oo      
$success = mysqli_execute($statement); 
      
$db->close(); // oo
mysqli_close($db); // procedural

Description

• For every object-oriented call to the mysqli extension, there is a corresponding procedural call.
• The object-oriented calls don’t include parentheses when they call a property, but they do include parentheses when they call a method.
• The procedural calls always begin with "mysqli_" and include the parentheses at the end of the function.
• The procedural calls usually pass the database connection, the result set, or the prepared statement to the function as its first argument.
• The object-oriented calls require less code than the corresponding procedural calls.