Analytical, Attribute and Calculation Views

Hello,

I have completed the tutorial on HANA development on OpenSAP, which is certainly the best way to learn specially for starters. But, even though I completed the course I was not able to exactly understand the concept of analytical, attribute and Calcualtion views.

I would like to know:

1) Why do we have these three different kinds of views, even though we could possibly have only one type of view from the above?

2) What is the significance or better said, what is the type of data we have in these three different views?

3) If we take retail industry as an example : what kind of data you would throw in these three different views and why?

I would be glad if anyone could answer this in simple words for my better understanding and hopefully would also help someone.

Thanks

Mesh