Object Relational Database Object Relational Database ComparisonComparison

by Neil Black, Steven Bruce & Marisa Di Filippo

IntroductionIntroduction

Brief introduction to the 3 main databases:– RDBMS– ODBMS– ORDBMS

Compare the above systems

Summary

Relational DatabasesRelational Databases

EMPLOYEE

EMP_ID FIRST_NAME LAST_NAME DEPT SALARY

1 Neil Black 1 750000

2 Marisa DI Filippo 1 100

78 Steven Bruce 2 35789

79 Hannah Bains 3 10

200 Gordon Russell 3 1

DEPARTMENT

DEPT DESCRIPTION LOCATION

1 Marketing Glasgow

2 Payroll Edinburgh

3 Public Relations Glasgow

Relational Databases …contRelational Databases …cont

Object-OrientationObject-Orientation

An OOD supports the following– Abstraction– Encapsulation– Classes & Instances– Inheritance– Messages & Methods– Polymorphism

Object IdentityLockingObject AccessDynamic Space CompactionNavigation

OODB FeaturesOODB Features

Object-Relational DatabaseObject-Relational Database

Amalgamation of RDBMS & ODBMSAdds limited Object-Oriented functionsData still stored in tablesSupports new types of data (multimedia)

RELATIONAL vs OBJECT-ORIENTED

Good for large amounts of data

Good for storing small amounts of complex data

Good for retrieval of data Excellent at data manipulation

Table/Record based Object Based

Relationships expressed in keys

Relationships built in to objects & containers

RELATIONAL vs OBJECT-ORIENTED

Limited complexity of relationships

Complex relationships

Defined types Variety of data types

Language independence Often connected to a language

SQL OQL

Comparison of DBMSComparison of DBMS

Defining standards:

RDBMS - SQL2(ANSI X3H2)

ODBMS - ODMG-v2.0

ORDBMS - SQL-3

Support for object-oriented programming:

RDBMS - Poor

ODBMS - Direct & extensive

ORDBMS - Limited mostly to new data types

Simplicity of use:

RDBMS - Table structures easy to understand; many end-user tools available

ODBMS - Ok for programmers; some SQL access for end users

ORDBMS - Same as RDBMS, with some confusing extensions

Simplicity of development:

RDBMS - Provides independence of data from app, good for simple relationships

ODBMS - Objects are a natural way to model; can accommodate various relationships

ORDBMS - Provides independence of data from app, good for simple relationships

Product Maturity:

RDBMS - Very mature. Well established.

ODBMS – Relatively mature.

ORDBMS – Immature; extensions are new, still being defined & are relatively unproven.

SummarySummary

Overall Relational Database are by far the most popular.

ODB used particularly in scientific fields to handle small amounts of complex data

ORDB now used for audio, image & video