Computer Science 380:

Principles of Database Systems

Chapter 22

Gregory M. Kapfhammer


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Object-Based Systems

Build a full-fledged object-oriented database

Add object-based features to relational databases

Use object-relational mapping techniques

Complex Data Types

Structured Types

Available through the create type command

Allows for the creation of user-defined types

Provides for standard features like methods and constructors

Array and Multiset Types

Nesting and Unnesting

Persistent Programming Languages

Data types are compatible

Query language is fully integrated

Storage and retrieval is fully automated

Persistence of Objects

By class

By creation

By marking

By reachability

Persistence in Java

Java database objects

Persistence by reachability

Bytecode enhancement

Database mapping required!

Tracking according to class extents

Unified reference to persistent and transient objects

Object Relational Mapping

Strengths and Weaknesses