2.2.02. Database internals

  • Stored as files of records (of data values)
    • Auxiliary data structures/indices
  • 1y and 2y storage
    • memory hierarchy (pyramid diagram)
    • volatility
  • Online and offline devices
  • Primary file organisation, records on disk
    • Heap - unordered
    • Sorted - ordered, sequential by sort key
    • Hashed - ordered by hash key
    • B-trees - more complex