1. Company & file-based DB - Sl.1/15
   1. Files get renamed and stuff
   2. People editing stuff at the same time; no way to do access rights
      • Maybe they have different settings/timezones or corrupt data
   3. ? If stock is part of the equation - you can’t easily manage that that way
   4. Everything from p. 1 just gets harder? Instead of copying from one file you have to copy from multiple, pray they are synchronized etc.
      1. You have to change both the program and all files connected to that
   5. No one can order but the other parts of the system work as well as they did before the online part 1. But you might get problems if things crash while you’re updating something that requires you to edit multiple files for the same transactions - you’ll get an inconsistent state
2. T/F
   1. F - atomicity - the interrupted transaction means rollback to before the beginning, unless stuff wasn’t explicitly written/committed
   2. F -
      1. “that is currently modified by another transaction” - you can’t see what’s not been committed/written yet
      2. BASE - “database system” - some happily allow you to read older data and there are different consistency guarantees (Sl.2/24)
   3. T - you can use database constraints for that, though probably doing it in a client is probably a better idea?..
   4. F - successfully completed means committed and they are the ones that get saved in case of a crash, it’s the uncommitted ones that get lost in that case
3. Big data Vs & CAP (from 4.)
   1. All except Veracity: Volume, Velocity (hot topics), Variety, Value (=ads) 2. CAP: you don’t care about consistency but do about availability and partition tolerance
   2. No Volume and variety:
      1. velocity (sensors with live data you have to react to)
      2. Veracity (sensors might be wrong in different ways based on sensor version)
      3. Value: don’t let the system die of overheating
      4. CAP: you don’t care about consistency but do about availability and ESPECIALLY partition tolerance
   3. No velocity, variety
      1. Veracity: words change meanings etc. and you have to evaluate exactly that bit; also OCR, typos etc.
      2. CAP: you don’t care about availability, but prolly do about consistency and PT
4. CAP for the above - see answers
5. Define a schedule that follows and one that breaks one of: monotonic read or read-your-writes
   1. RYW: book rooms for Vorlesungen. There are three rooms, a b and c. Capitalized = booked.

Mike: abc
John: abc