Huh??? What did you have in mind for the data to get from the TTN servers to your database? There is no automagic integration that puts your data in to a database.
When the data arrives at the Application Server, it will just disappear in to thin air unless YOU choose to do something with it. Those somethings include:
- Data Storage
All of which have a well documented API for your data to leave the confines of the TTN servers and get to your servers. All three provide the data as JSON with varying levels of detail. When it arrives, you parse the JSON to prepare it for however your database would like you to insert records, depending on both the database and the language you are using, perform the insert and then, erm, that’s it.