db41, db42 and db43 are they all needed

[Tankko]

After installing 6.2 and all the ports I use on a new machine, I have:

apr-db42-1.2.8_2
db41-4.1.25_4
db42-4.2.52_5

and there is db43 out there as well, probably just waiting to be installed.

db41-4.1.25_4 is used by:
portupgrade-2.3.1,2
ruby18-bdb-0.6.2

db42-4.2.52_5 is used by:
apr-db42-1.2.8_2

Which is required by subverson (I need BDB access in subversion).

Do I need all these different version of db?   I guess there is no
huge downside to having them all installed, but it doesn't seem clean
to my anal-retentive nature.

Is there a make.conf flag that will just make them all use db42 (or
db43)?  Is that wise?

Tankko