Behaviour storage in objectoriented databases

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Behaviour storage in object-oriented databases
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Content

• Introduction
• Federated databases
• Object-oriented models in federated databases
• Behaviour in object-oriented databases
• Conclusions and further research

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Introduction

• Different database modelling paradigms
  hierarchical, network, relational,
  object-relational, object-oriented etc.
• Federated databases
• Object-oriented model in federated databases.
• ODMG Standard for object-oriented databases.
• Behaviour is a collection of persistent class
  methods.

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Federated database

• Component database versus federated
• Query execution
• Behaviour

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ODMG model issues

• Behaviour execution in the client application
  (e.g. behaviour linked in the application code)
• Problems
• Query execution
• Generic applications
• Federated databases

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Requirements

• Behaviour on the server to enable
• query processing on the server
• construction of federated schema

queries, behaviour invocation object state
modification
object references, return values of method
invocations
Client
ODMG behaviour store
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Key characteristics

• A persistent object is located on the server.
• Behaviour is located on the server and invoked
  using standard distributed object technology.
• Behaviour sharing service is a generic
  application for an ODMG database.

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ODMG Behaviour storage
ODMG database application
ODMG database
ODMG Behaviour storage application
ODMG database
ODMG behaviour storage
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Behaviour Storage Issues

• Feasibility
• Access to the behaviour.
• Combining state with behaviour.
• Performance of the approach (remote invocations
  are 1,000 times slower then local calls).

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Global structure
Request broker
Behaviour engine
Client
Query engine
Database access
ODMG database
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Review and further research

• Research of the existing solutions.
• Detailed design specification.
• Implementation and performance.
• Behaviour sharing for federated databases
• Behaviour for virtual classes