It sounds like this is released by the same people the old one is not maintained (last release 2005!) nothing in pkgsrc uses it the new file is libdbh2 and unpacks to libdbh2 so i would add databases/libdbh2 and remove the old package. To me, the real name of a package in cases like this is the tarball/unpack name.
Attachment:
pgpWbzC980Iqg.pgp
Description: PGP signature