[DRAFT] Refactor database queries

[GjjvdBurg]

This is an attempt to refactor the database queries. The idea is to have a single Database instance that is passed to the functions instead of the opened sqlite3 cursor, and to implement all necessary queries as methods of the Database instance.

Feedback on the approach suggested here is much appreciated.

@ericthegrey, before I dive into this refactor, what do you think of the proposed structure?

[ericthegrey]

Hi @GjjvdBurg

That seems like the next logical encapsulation step for the DB peculiarities. A few comments:

• The connection could have the same lifetime as the Database object itself.
• Perhaps instead of returning a realized collection of rows, we could return an iterator encapsulating the cursor (In principle, you'd not have to load everything in memory at once -- although the DB driver might just do that. Not sure if it's worth the overhead.)
• You might use the opportunity to catch sqlite3.Error when working with the DB.