Oh dear
How about we leave this thread be until donmachivelli demonstrates some inclination to answer the question himself and then request what could be improved\ corrected\ added\ removed?
Don - if you presented your understanding thus far I'm sure people will be willing to help. Personally - I have no professional experience I can share with you - the relational model was accepted as the mainstream paradigm quite some years ago (please - no one introduce OO and relational OO into the mix

). Some of the more experienced (ahem) members or those that have some sort of niche expertise may be able to pass on their wisdom. I would imagine, however, that this assignment is designed to assess your ability to source\ comprehend\ summarise this topic rather than present obscure and specific observations of professionals with real world experience in the field.
Ah well - I guess for every rewarding student-asks-a-question-and-allows-themself-to-be-guided thread there has to be one like this.