Check out the various SNAP PAC REST Api examples (over on the left side of the page), here: http://developer.opto22.com/rest/pac/
These include a couple of database options. But to be clear, the request is coming from SQL (or Access), which reads/writes to/from the tags in your strategy via the REST API. (Rather than a request/query being initiated by your strategy.)
Beno had an old example where the strategy initiated things, but there was a php layer in it (so your strategy would hit a server running the php code which connected to your database) but that's got more moving parts.
Of course there's also OptoDataLink but that costs extra $$ and is pretty much just a pipe between your PAC and a database. It is super easy to set up, basically a wizard where you check the boxes for what you want to move from/to where and when.
And then with groov there's the whole Node-RED option, which is fun, too! Like most things w/Opto, we have lots of options to choose from...
Hope that helps,