I agree with Tom... It would appear that there is and always will be a 1:1 relationship between the fitness details, the session metrics, and the date of the session and none of the columns in any of those tables looks like it'll ever be null. There will be those that disagree but I believe all that information is just about the session and should probably live in a single table. I agree that the workout method should be in a separate table but the key for the workout method should be stored in the session table as an FK to the workout method instead of how you currently have it.