1.1.12. Program-data independence

  • General databases
    • Separate Data definition and data
    • Catalog/meta-data & tuples
  • Data format/structure stored separately
  • Program-data independence (e.g. Y2K)
    • Changes in data format
      • Alter data (tuples)
      • Alter grammar (catalog/meta-data)
    • We actually split program-data independence into:
      • Logical
      • Physical
    • ...more in a second