Each of these columns is optional. If these columns do not exist, MyDNS will operate normally. If they do exist, however, MyDNS will notice this and enable additional code specific to each optional field.
If you add any of these fields to your database, you must restart MyDNS before it will honor them.
Please try to remember that these optional columns are optional because they will negatively affect performance. MyDNS will run faster if you don't use these columns. (The negative impact, however, should be minor.)