Re: [Q] DNS(bind) ER model

Mark wrote:
> On Thu, 2008-08-14 at 16:20 -0700, Roderick A. Anderson wrote:
>> Anyone aware of an ER model for holding name server records?
>>
>> Working on the zone file data and I am getting close but keep running
>> into the differences between MX records (with a priority) and the others
>> that can hold either a domain/sub-domain/host name or an IP address
>> depending on whether is an A, TXT, PTR, etc. or a CNAME.
>
> Don't add a column for the prio of the MX record. A lot of designs do
> this but IMHO it's crap. If you do it for MX records you also have to do
> it for SRV records and who knows what other (future) records).

I was working towards that direction. I really hated the idea of a
sparse table and even a sparse column.

>
> We (@work) use an in house designed database that use the best technique
> I've ever seen.
>
> What it does is use a table to list all the valid RR types(1) along with
> an ID and regular expressions that describe what the name and rdata
> should look like.

Interesting idea. A project I worked on awhile ago did something
similar. Actually stored some Perl code.

> In the table that holds the dns records the type of the record is
> foreign key referencing the type table. And insert/update triggers are
> used to check that records match the patters in the types table.

Better and better.

> With this technique supporting a new record type is as easy as inserting
> a new row in the types table. And it also garanties that all records in
> the database is at least syntactically correct. (Assuming your patters
> are correct of course.)

Thanks,
Rod
--
>> Much of the database will be populated and changed automagically so the
>> controller for the application will do the right thing but humans will
>> get involved every so often. I hope I can get the database to make the
>> right thing easy and the wrong thing "impossible" for them.
>>
>> Any suggestions?
>
> HTH.
>
> Cheers,
> Mark.
>
>