SQL database hostname change

I have the following issue with my Databases:

I have 1 domain registered with DH (domain A) and 2 domains hosted with DH but registered elsewhere (domains B and C).
All my databases have their hostnames at domain A (panel->Manage account->Databases->Hostname(for each DB)).
At the same time all these databases are actually hosted at domains B and C (panel->MySQL databases->name of MySQL server->Hostname(these are all interchangeable)).
The latter hostnames in mysql subdomains (mysql.domain BorC) are “real” which means that all my web applications on domains B and C are actually pointing to these hostnames (in wp_config.php).

My domain registration for domain A will expire soon and I don’t want to renew it. Instead I registered a new domain (domain D) via DH and hosted it here.
What actions should be performed (if any) to change the hostname of my databases from domain A to domain D before registration of domain A expires?
What are the risks?

Thank you very much!

As long as you see all of your databases attached to the same MySQL server (true most likely for most customers), then the hostnames are all interchangeable.

So just use the ‘add hostname’ button and add hostnames for B, C and D then edit the appropriate wp-config.php with the new hostname for each domain. Then each will have a hostname associated with it’s own domain.

You do need to do this before domain A expires.

What the hostname does is allow use of a NAME used to locate the IP address of the database. The reason you can use one single hostname for all 3 domains currently is they are all on the same database server and thus all have the same IP address.

Since your sorting this out in anticipation of a domain expiring I would just go ahead and create 3 new hostname something like mysql.domainB.com mysql.domainC.com mysql.domainD.com. All of those hostnames be interchangeable with this existing, then just update each domain to it’s own hostname.

Thank you.
I’ve already done that. I created new hostnames (mysql.domanB, mysql.domainC).
And I changed wp_config.php files to point to these hostnames. Everything works fine.

BUT I can still see the old hostname (mysql.domainA) in the list of my databases (all of them, panel->Manage account->Databases->Hostname).
Since only domain A currently uses your DNS (was originally registered via DH) I can only choose “domain A” in a field “New Hostname” when I am creating a new database.
At the same time, I can choose “domain B” or “domain C” in a field “Use Hostname” (and I chose that when I was creating my databases for these domains).
Now it works fine, but what will happen when my domain A expires?
Will the databases be accessible?

Thank you again!

the hostnames are interchangeable. so long as you have a hostname with a domain that is registered you would be able to access the database using it and whatever user and password you created for that particular database.

I’ve just registered and hosted a new domain with DH.
So now I will have at least one domain registered with DH when “domain A” expires.
Hopefully the databases will be accessible even if they use hostnames on domains which are not registered with DH.

Do the domains registered elsewhere have their nameservers pointed to dreamhost? And they must, because it is working now…That’s what matters, not who the registrar is, but where the nameservers are pointed.