Migrating From Relational To Object-Oriented Databases

1. Migrating From Relational To Object-Oriented Databases Masood Asif, Kenny Dunlop, Gerard Given & Grant Stalker

2. Structure Of Talk • Grant • Abstract • Introduction • What are Relational Databases? • Pro’s & Cons of Relational Databases • What are Object Oriented Databases? • Pro’s and Cons of Object Oriented Databases • What is MIGRATION • Pro’s and Cons of migration • Architecture • Example • Conclusion

3. Structure Of Talk • Gerry • Routes For Migration • Cold Turkey • Chicken Little • Dead & Alive Parallel Approach • Recovery /Step Back • Cold Turkey • Chicken Little • Dead & Alive Parallel Approach

4. Introduction • Who Wants to MIGRATE to an OODB from Relational Databases? • What Is a Relational Database? • What is the standard user application program interface to a relational database?

5. Pro’s & Cons Of Relational DB • Pro’s • Very simple to understand and implement • Well documented • Many proven vendor solutions available • Easy to modify existing databases • Con’s • Very little flexibility for data structuring • Current query language is not computationally complete • Little or no support for temporal data • They cannot sufficiently express data that does map well to tables • The new query language (SQL3) is far too complex

6. Object Oriented Databases • What type of uses have OODB have in organisations?

7. Definition of an OODBS • An Object Oriented Database must satisfy 2 criteria: • Should be a DBMS • DBMS Translates into 5 features • Should Be an object oriented system i.e. to extent possible should be consistent with the current crop of object oriented programming languages • OOS Translates into 7 features

8. Pro’ & Cons of OODB • Pros (Object Oriented) • Model real-world environment effectively • Objects encapsulates both state and behavior allowing for code reuse • Organization of data can be done by the needs of the application • OO Programming languages provide faster development e.g. Applications. • Cons (Object Oriented) • Many vendors in the market but which ones will survive to provide support

9. Migration • What Is Migration? • What are the cons for migration? • What are the Pro’s for migration?

10. Architecture • There are two Types of Legacy Architecture • Legacy Relational Databases (Decomposable Legacy IS) • Legacy Non-Relational Database (Non-Decomposable Legacy IS) • Why are Legacy Relational Databases easier to migrate than Non-Relational Databases?

11. GUI I GUI Interface Interface Application Modules Application Modules Legacy Relational Database Decomposable Legacy I.S. Legacy Non Relational Database Non-Decomposable Legacy I.S. Data Data Diagram Example

12. Structure Of Talk • Gerry • Routes For Migration • Cold Turkey • Chicken Little • Dead & Alive Parallel Approach • Recovery /Step Back • Cold Turkey • Chicken Little • Dead & Alive Parallel Approach

13. Routes For Migration • Routes • Cold Turkey • What is cold turkey? • Issues With Cold Turkey • Lack Documentation • Application Dependencies • Project Management • Time Doesn’t Stand Still • New Functionality • Live Data • Company Reorganisation • Savings

14. Routes For Migration • Chicken Little • About Chicken Little • Main Issues • Step By Step • Gateways • Use of Gateways

15. Legacy GUI (Live) Target New GUI (Not live yet) Gateway Target I.S. (OODB) Data Example of a Gateway

16. Dead & Alive Parallel Approach • What is Dead & Alive Parallel Approach? • Time Scales • Requires More Resources

17. Recovery/Step Back • What happens in the discussed strategies in the event of an error or mistake? • Cold Turkey • Chicken Little • Dead & Alive Parallel Approach

18. Conclusion • Is there a definite answer, should a company migrate to an OODB or not?