Thankfully, Dagger is under active maintenance, and has financial support through the JuliaLab (by employing me). Krystian Guliński, the DTable's author and maintainer, is also interested in developing and maintaining the DTable further (having created it as part of his schooling), and will hopefully stay on the Dagger team for the foreseeable future.
With that PR in place, it should be possible to define a "storage device" which is backed by a database. I haven't had a chance to actually try this, since the PR still needs quite some work and testing, but it's definitely something on my radar!