What is the most efficient way to read two tables from a database?

I'm facing a small C++ project and I was wondering what is the best way to read data from 2 tables. Im using SQLite. Can't change that.

First table has devices (150k - 300k entries). Each device has several features (5-40 features).

What is the best way to read this ? Everything is local.

I was considering:

• 
  

  sequentially( each device one by one and for each one read its features.

  
  


• 
  

  all devices first, then for each one its features

  
  


• 
  

  chunks of devices, then for each one its features

  
  

basically would you do a breadth first or depth first approach ?

I'm no DB expert so whatever tip can help !

Thanks