1. Queries on several relations require several skeleton tables.
2. To find the name and city of all customers having a loan at the SFU branch:
| borrow | bname | loan# | cname | amount |
| SFU | _x |
| customer | cname | street | ccity |
| P._x | P._y |
3. Find the name of all customers having an account at the SFU branch, but no loan from that branch.Queries involving negation can be expressed by putting a : sign under the relation name beside an example
row
| deposit | bname | account# | cname | balance | borrow | bname | loan# | cname | amount |
| SFU | P._x | ï¿¢ | SFU | _x |
4. To nd all customers who have accounts at two di erent branches:
| deposit | bname | account# | cname | balance |
|
_y ï¿¢_y |
P._x _x |