1. RDB – OODB - ORDB Comparison

2. RDB – what’s good ? – Simple data model (but less versatile) – Simpler for user to learn (OO programmer?) – Easier to optimize (for simple access?) – Strong market-share (inertia of change)

3. Advantages of Adding OO Richer Data Types Simplify DB design Simplify query specification Reusability of code (more natural to OO programmer) No impedance mismatch

4. ORDB – OODB Similarities Similar OO type system ambitions: Objects/OIDs Methods ADTs Constructed types Inheritance Object-QL

5. ORDBOODB ADT methods QL

6. ORDBOODB ADT Optional / mixed (also key) Uniformally enforced Methods QL

7. ORDBOODB ADT Optional / mixed (also key) Uniformally enforced Methods Externally def. methods; register executables One pure OO language; Seamless with PL QL

8. ORDBOODB ADT Optional / mixed (also key) Uniformally enforced Methods Externally def. methods; register executables One pure OO language; Seamless with PL QL SQL3 moving targetODMG OQL stable SQL3 : 300 pagesOQL : 3 pages SQL3 : one standard?OQL: binding with different PL models

9. ORDBOODB Types/ type constru ctors Types equal citizens ? Referen ces?

10. ORDBOODB Types/ type constru ctors Row = special data type (superset of relation) Many type constructors Types equal citizens ? Referen ces?

11. ORDBOODB Types/ type constru ctors Row = special data type (superset of relation) Many type constructors Types equal citizens ? Results are tables again Any container data type Referen ces?

12. ORDBOODB Types/ type constru ctors Row = special data type (superset of relation) Many type constructors Types equal citizens ? Results are tables again Any container data type Referen ces? Foreign keys : restricted to one table scope OID references : hard to support; dangling pointers

13. ORDBOODB DB design Classes of applications targeted

14. ORDBOODB DB design Design : ER diagram ? Directly use OMT, or OO design tools Classes of applications targeted

15. ORDBOODB DB design Design : ER diagram ? Directly use OMT, or OO design tools Classes of applications targeted Target many small objects (disk in/out); disk intensive;short transactions; Target large complex objects (long in memory); long transactions, client-side caching

16. DBMS features inherited from RDB into ORDB : Constraints Views Triggers Priviledges (security) ORDB Extra Goodies