dns records

[Markus Welsch]

hi all,
i have a few questions regarding dns records for using in a mysql db.the 
current layout looks like this:

    class           CH
                        HS
                        IN
        data
        name
        preference
        ttl
        type            A
                        CNAME
                        MX
                        NS
                        PTR
                        SOA
The class is not really required. Regarding the type, that are all the 
types currently in use. If you do a lookup of e. g. www.debian.org at
http://www.network-tools.com/nslook/Default.asp?domain=www.debian.org&type=255&server=66.46.181.133&class=255&port=53&advanced=true 
you will see more clear what each field exactly means.

I thought of using enum for the type, varchar for data and name, 
smallint (2) for preference, varchar(8) for ttl since it could be 
alpha-numeric.

How large can a preference be (MX records) ?
What about the length of data and name ?

Greetings,
Markus