There is no problem to use a relational database for this. It all depends how you design it. Have a look at the EAV model (http://en.wikipedia.org/wiki/Entity-attribute-value_model). It is specifically designed to handle this scenario. The downside is that the queries tend to be complex.

Assuming they like to be exposed to your culture. Remember that Bin Laden was not that thrilled about his time in the US and later decided to do something radical.

Besides, is it not a positive thing that highly educated people from under developed countries are going back to contribute to their own country? At least I think so. Yes the economy sucks these days but if you ask yourself who needs to improve their living standards the most, USA or underdeveloped countries, I think (or at least hope) most of you go for the latter.

I am working within the Erasmus Mundus External Window Cooperation which is en education program funded by EU. One of the goals for this program is to make sure people from 3rd world countries are given a chance to study at a higher level on a full scholarship in Europe. The EU also strongly recommend that after they have completed their courses, they return to their home country to prevent brain drain. I think the US can afford this as well.

It will not kill us to share the wealth a little.