Does anyone have documentation or tooling to help migrate from a config file based asterisk deployment to a database deployment?
I don't have an automated migration script, but the gist is that you make with an extconfig.conf file that maps a traditional config file name to a table name (and set of MySQL or ODBC/DB credentials), and then a set of tables with slightly normalized (but nearly line-for-line) equivalents to what would be in a local config file. http://www.voip-info.org/wiki/view/Asterisk+RealTime has more.
Another way to do realtime database-backed call routing is using AGI or Fast AGI. We recommend AGI to our Asterisk hosting customers because it decouples call routing logic from phone/PBX functionality, something that's not at all true with an Asterisk dialplan (Asterisk RealTime or not). Your dialplan then uses the AGI command (with an agi:// URL) instead of calling embedded dialplan commands.
That also lets you write the call logic/routing in whatever programming language does the job best, which is rarely AEL. help.cloudvox.com has a bunch more AGI docs.
I was looking for the same thing and ended up writing my own quick and dirty script using Asterisk::config modules from CPAN, hope it saves sometime of somebody else: