1
GATE CSE 2005
MCQ (Single Correct Answer)
+2
-0.6
In an inventory management system implemented at a trading corporation, there are several tables designed to hold all the information. Amongst these, the following two tables hold information on which items are supplied by which suppliers, and which warehouse keeps which items along with the stock-level of these items.

Supply = (supplierid, itemcode)
Inventory = (itemcode, warehouse, stocklevel)

For a specific information required by the management, following SQL query has been written

Select distinct STMP.supplierid 
From Supply as STMP 
Where not unique (Select ITMP.supplierid 
    From Inventory, Supply as ITMP 
    Where STMP.supplierid = ITMP.supplierid 
    And ITMP.itemcode = Inventory.itemcode 
    And Inventory.warehouse = 'Nagpur');
For the warehouse at Nagpur, this query will find all suppliers who
A
do not supply any item
B
supply exactly one item
C
supply one or more items
D
supply two or more items
2
GATE CSE 2005
MCQ (Single Correct Answer)
+1
-0.3

Let r be a relation instance with schema R = (A, B, C, D).

We define $${r_1} = {\pi _{A,B,C}}\left( r \right)$$ and $${r_1} = {\pi _{A,D}}\left( r \right)$$. Let $$s = {r_1}*{r_2}$$ where * denotes natural join. Given that the decomposition of r into r1 and r2 is lossy, which one of the following is TRUE?
A
$$s \subset r$$
B
$$r \cup s =r$$
C
$$r \subset s$$
D
$$r * s = s$$
3
GATE CSE 2005
MCQ (Single Correct Answer)
+2
-0.6
A table ‘student’ with schema (roll, name, hostel, marks), and another table ‘hobby’ with schema (roll, hobbyname) contains records as shown below:

Table: student

Roll Name Hostel Marks
1798 Manoj Rathod 7 95
2154 Soumic Banerjee 5 68
2369 Gumma Reddy 7 86
2581 Pradeep Pendse 6 92
2643 Suhas Kulkarni 5 78
2711 Nitin Kadam 8 72
2872 Kiran Vora 5 92
2926 Manoj Kunkalikar
5 94
2959 Hemant Karkhanis
7 88
3125 Rajesh Doshi 5 82

Table: hobby

Roll Hobbyname
1798 chess
1798 music
2154 music
2369 swimming
2581 cricket
2643 chess
2643 hockey
2711 volleyball
2872 football
2926 cricket
2959 photography
3125 music
3125 chess

The following SQL query is executed on the above tables:

Select hostel
From student natural join hobby
Where marks > = 75 and roll between 2000 and 3000;

Relations S and H with the same schema as those of these two tables respectively contain the same information as tuples. A new relation S’ is obtained by the following relational algebra operation:

$$\eqalign{ & S' = \prod\nolimits_{hostel} {(({\sigma _{S.roll = H.roll}}} \cr & ({\sigma _{marks > 75\,\,\,and\,\,roll > 2000\,\,and\,\,roll < 3000}}(S))X(H)) \cr} $$

The difference between the number of rows output by the SQL statement and the number of tuples in S’ is

A
6
B
4
C
2
D
0
4
GATE CSE 2005
MCQ (Single Correct Answer)
+1
-0.3
Amongst the ACID properties of a transaction, the 'Durability' property requires that the changes made to the database by a successful transaction persist
A
Except in case of an Operating System crash
B
Except in case of a Disk crash
C
Except in case of a power failure
D
Always, even if there is a failure of any kind
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