1. RDB – OODB - ORDB Comparison

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

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

5. ORDB
OODB
ADT
Optional / mixed
(also key)
Uniformally
enforced
methods
Externally def. Methods; register executable
One pure OO language;
Seamless with PL QL
SQL3 moving target
ODMG OQL stable
SQL3 : 300 pages
OQL : 3 pages
SQL3 : one standard?
OQL: binding with different PL models

6. ORDB
OODB
Row = special data type
(superset of relation)
Many type constructors
Results are tables again
Any container data type
Foreign keys : restricted to one table scope
OID references : hard to support; dangling pointers
Design : ER diagram ?
Directly use OMT, or OO design tools
Target many small objects (disk in/out); disk intensive;short transactions;
Target large complex objects (long in memory); long transactions, client-side caching

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