Data management in the 1970s
- Predominant database technologies: IMS, CODASYL.
- Radically new approach: The relational model.
After 20 years of research
- Specify logical model and physical
organization separately.
- SQL
-
- Heuristic, then cost-based. Starting to get good
enough to trust.
- By adjusting physical
organization. Application code is (mostly) untouched.
- Atomic transactions, with varying isolation levels
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