explanation needed in points clearly!!!

[imagine]

guys can you help me understand what is the meaning of following terms in computing P3 section: database?

a) primary key
b) secondary key
c) foreign key

 

[lewis_neu]

http://d1.scribdassets.com/ScribdVi...key-14c2qh12pq2l7gickzeh&page=1&viewMode=list
read this awesome note over here!! i guess this will help u ...

guys can you help me understand what is the meaning of following terms in computing P3 section: database?

a) primary key
b) secondary key
c) foreign key