/** * Connects to the sql database and runs a sql query. * * @param sql_query $sql mysql query to be performed on the database. * @return object|boolean returns a mysqli_result object if data is retrieved from the database * or boolean value if there is no data(true on success/false on failure). */ protected static final function query($sql) { if (self::$conn == null) { self::$conn = new mysqli(self::$servername, self::$username, self::$password, self::$dbname); if (self::$conn->connect_error) { die("Connection failed: " . self::$conn->connect_error); } } return self::$conn->query($sql); }