问防止用户在php中将名称更新为空白或空格

EN

if (!empty($_POST['name']) && !preg_match('/^\s*$/', $_POST['name'])){
    $name = $_POST['name'];
    $uid = $user['id'];
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $sql = "UPDATE accounts SET Name=? WHERE id=?";

    // Prepare statement
    $stmt = $conn->prepare($sql);

    // execute the query
    $stmt->execute(array($name, $id));

    // echo a message to say the UPDATE succeeded
    echo '<div style="width: 98%; max-width: 98%; border: 1px solid white; background-color: orange; color: white; vertical-align: text-top; text-align: center;">Your name has been updated!</div><br>';
} else {
    echo 'Name is not valid';
}

//valadations

$errors = array();


// * presence
// use trim() so empty spaces don't count
// use === to avoid false positives
// empty() would consider "0" to be empty
function has_presence($value) {
    return isset($value) && $value !== "";
}

function validate_presences($required_fields) {
  global $errors;
  foreach($required_fields as $field) {
    $value = trim($_POST[$field]);
    if (!has_presence($value)) {
        $errors[$field] = fieldname_as_text($field) . " can't be blank";
    }
  }
}

function form_errors($errors=array()) {
    $output = "";
    if (!empty($errors)) {
      $output .= "<div class=\"error\">";
      $output .= "Please fix the following errors:";
      $output .= "<ul>";
      foreach ($errors as $key => $error) {
        $output .= "<li>";
            $output .= htmlentities($error);
            $output .= "</li>";
      }
      $output .= "</ul>";
      $output .= "</div>";
    }
    return $output;
}

  $required_fields = array("name", "email", "username");
  validate_presences($required_fields);

echo form_errors($errors);

if ($_POST['name']){
    $name = mysql_real_escape_string($_POST['name']);
    $uid = $user['id'];
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
     $required_fields = array("name");
      validate_presences($required_fields);


    // set the PDO error mode to exception
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    if(empty($errors)) {
    $sql = "UPDATE accounts SET Name='$name' WHERE id='$uid'";

    // Prepare statement
    $stmt = $conn->prepare($sql);

    // execute the query
    $stmt->execute();

    // echo a message to say the UPDATE succeeded
    echo '<div style="width: 98%; max-width: 98%; border: 1px solid white; background-color: orange; color: white; vertical-align: text-top; text-align: center;">Your name has been updated!</div><br>';
}