RDB%20

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RDB OODB - ORDB Comparison
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RDB whats 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)

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Advantages of Adding OO

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

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ORDB OODB Similarities

• Similar OO type system ambitions
• Objects/OIDs
• Methods
• ADTs
• Constructed types
• Inheritance
• Object-QL

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ORDB OODB
ADT
methods
QL


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ORDB OODB
ADT Optional / mixed (also key) Uniformally enforced
Methods
QL


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


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ORDB OODB
ADT Optional / mixed (also key) Uniformally enforced
Methods Externally def. methods register executables 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
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ORDB OODB
Types/ type constructors
Types equal citizens?
References?


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ORDB OODB
Types/ type constructors Row special data type (superset of relation) Many type constructors
Types equal citizens?
References?


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ORDB OODB
Types/ type constructors Row special data type (superset of relation) Many type constructors
Types equal citizens? Results are tables again Any container data type
References?


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ORDB OODB
Types/ type constructors Row special data type (superset of relation) Many type constructors
Types equal citizens? Results are tables again Any container data type
References? Foreign keys restricted to one table scope OID references hard to support dangling pointers


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ORDB OODB



DB design
Classes of applications targeted
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ORDB OODB



DB design Design ER diagram ? Directly use OMT, or OO design tools
Classes of applications targeted
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ORDB OODB



DB design Design ER diagram ? Directly use OMT, or OO design tools
Classes of applications targeted Target many small objects (disk in/out) disk intensiveshort transactions Target large complex objects (long in memory) long transactions, client-side caching
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ORDB Extra Goodies

• DBMS features inherited from RDB into ORDB
• Constraints
• Views
• Triggers
• Priviledges (security)