# Questions by Bhagirathi

1
Till now i have not got any exciting and detailed explanation of page tables and multi level page tables concept. if you have any resource on this please post the link ..
2
what is the advantage of keeping the Foreign Key null as we know if we make the Foreign Key null we cant reference it again so thats a disadvantage ......so there must be some advantage which outweighs this disadvantage so whats that advantage
3
How $\phi^*=\epsilon$?
1 vote