DB Import

[al-develop]

It would be useful to be able to import a SQLite database to the current used database.
The classes are already expanded, what's missing is the core for importing (in DataAccess class).

TO DO:

• write core DataAccess code.
• For this, following decisions need to be made:
  • using 2 parallel SQL connections to 2 databases?
    • if using 2 parallel conncetions, it will be possible, to select from DB 1 and insert into DB 2 at once --> memory won't be used to a big extend
    • if using 1 connection at a time, it will be needed to select all data from DB 1 into memory, close that conneciton, open the connection to DB 2 and insert it. For a better clean up, the data inside the memory should be clenaned right away.