For years the norm for object developers was to work in an evolutionary (iterative and incremental) manner but for database developers to work in a more serial manner. The predominance of evolutionary development methodologies such as Extreme Programming (XP), Feature Driven Development (FDD) make it clear that the two groups need to work in the same manner to be productive as a team.
Pramod Sadalage presents material from the 2007 Jolt Productivity Award winning book Refactoring Databases : Evolutionary Database Design on how to practice evolutionary database development and discusses the following techniques:
- Database refactoring: Evolve an existing database schema a small bit at a time to improve the quality of its design without changing its semantics.
- Evolutionary data modeling: Model the data aspects of a system iteratively and incrementally, just like all other aspects of a system, to ensure that the database schema evolves in step with the application code.
- Database regression testing: Ensure that the database schema actually works.
- Configuration management of database assets: Your data models, database tests, test data, and so on are important project artifacts which should be managed just like any other artifact.
- Database Schema Deployment: Ensure that the scripts used to build development environments are the exact same used in QA, UAT and production. Ensure deployment to production is not a surprise and not a project in itself.
Pramod is an experienced database administrator and developer and has been working with Agile methodologies for ten years at ThoughtWorks. His advice comes from years of experience.