Comprehension Passage
Read the following and Answer the questions:
Consider the relational schema of sailors S. Reserves R and Boats B.
Table 1: Sailors S
|
Sid |
Sname |
Ratting |
Age |
|
22 |
Dustin |
7 |
45.0 |
|
29 |
Brutus |
1 |
33.0 |
|
31 |
Lubber |
8 |
55.5 |
|
32 |
Andy |
8 |
25.5 |
|
58 |
Rusty |
10 |
35.0 |
|
64 |
Horatio |
7 |
35.0 |
|
71 |
Zorba |
10 |
16.0 |
|
74 |
Horatio |
9 |
35.0 |
|
85 |
Art |
3 |
25.5 |
|
95 |
Bob |
3 |
63.5 |
Table 2: Reserves R
|
Sid |
Bid |
day |
|
22 |
101 |
10/10/98 |
|
22 |
102 |
10/10/98 |
|
22 |
103 |
10/8/98 |
|
22 |
104 |
10/7/98 |
|
31 |
102 |
11/10/98 |
|
31 |
103 |
11/6/98 |
|
31 |
104 |
11/12/98 |
|
64 |
101 |
9/5/98 |
|
64 |
102 |
9/8/98 |
|
74 |
103 |
9/8/98 |
Table 3: Boats B
|
Bid |
Bname |
Color |
|
101 |
Interlake |
blue |
|
102 |
Interlake |
red |
|
103 |
Clipper |
green |
|
104 |
Marine |
red |
Which of the following relational algebra query computes the names of sailor who have reserved all boats?
1
ρ (Tempsids, (πbid Reserves)/πbid Boats) πsname ((Tempsids) ⋈ Sailors)
2
ρ (Tempsids, (πsid, bid Reserves)/πbid Boats) πsname ((Tempsids) ⋈ Sailors)
3
ρ (Tempsids, (πsid Sailors)/πbid Boats) πsname ((Tempsids) ⋈ Sailors)
4
ρ (Tempsids, (πsid Reserves)/πbid Boats) πsname ((Tempsids) ⋈ Boats)