by Chris Date
Here are a few questions having to do with relational model. Can you answer them?
What's The Information Principle? Why are duplicates prohibited? What's essentiality? Why is it important? What's the connection between relations and predicates? Is it ever necessary to denormalize?
What's the real difference between a domain and a relation?Can join views be updated? If so, how? Can a relation have an attribute whose values are sets? Why do cursor updates violate the relational model? Can a relation have no attributes at all? What's closure? Why is it important? Why should you avoid nulls?
It is trite but true to say that the relational model is the foundation of the entire database field. Yet almost no one understands it!
We wouldn't think much of an electronics engineer who didn't know Ohm's Law or a chemist who didn't know the periodic table, yet the IT industry seems all too willing to tolerate database "professionals" who are almost completely ignorant of the foundations of their field.
No wonder, then, that such spectacular mistakes occur in the design and/or implementation of databases, and database applications, and database products, and database standards, etc.
The seminar examines the relational model with the intent to present a remodeled version of the relational theory, one that will help true database professionals understand the relational model in depth and make use of that understanding in their day-to-day database activities.
- Relational Algebra
- Relational Integrity
- The Relational Model is set-level
- Missing Information
- Relatio-valued attributes
- Database design
- The third Manifesto