Suppliers(Sid: integer, sname:string, city:string, street:string) Parts(pid:integer, pname:string, color:string) Catalog(sid:integer, pid:integer, cost:real) Consider the following relational query on the above database: SELECT S.sname FROM Suppliers S WHERE S.sid NOT IN (SELECT C.sid FROM Catalog C WHERE C.pid NOT IN (SELECT P.pid FROM Parts P WHERE P.color < > ‘blue’)) Assume that relations corresponding to the above schema are not empty. Which of the following is the correct interpretation of the above query?

Consider the following four relational schemas. For each schema, all non-trivial functional dependencies are listed. The underlined attributes are the respective primary keys. Schema I: Field ‘courses’ is a set-valued attribute containing the set of courses a student has registered for. Non-trivial functional dependency: rollno → courses Schema II: Non-trivial functional dependencies: rollno, courseid → email email → rollno Schema III: Non-trivial functional dependencies: rollno, courseid → marks, grade marks → grade Schema IV: Non-trivial functional dependencies: rollno, courseid → credit courseid → credit Which one of the relational schemas above is in 3NF but not in BCNF?

A

Schema I

B

Schema II

C

Schema III

D

Schema IV

Consider the following relational schema. Students(rollno: integer, sname: string) Courses(courseno: integer, cname: string) Registration(rollno: integer, courseno: integer, percent: real) Which of the following queries are equivalent to this query in English? “Find the distinct names of all students who score more than 90% in the course numbered 107” (I) SELECT DISTINCT S.sname FROM Students as S, Registration as R WHERE R.rollno=S.rollno AND R.courseno=107 AND R.percent >90 (II) Πsname (σcourseno = 107∧percent>90 (Registration ⋈ Students)) (III) {T | ∃S ∈ Students, ∃R ∈ Registration (S.rollno = R.rollno ∧R. courseno = 107 ∧ R.percent > 90 ∧ T.sname = S. sname)} (IV) {〈SN〉 | ∃SR∃RP(〈SR, SN〉 ∈ Students ∧ 〈SR, 107, RP〉 ∈ Registration ∧ RP > 90)}

A

I, II, III and IV

B

I, II and III only

C

I, II and IV only

D

II, III and IV only

Consider the relational schema given below, where eId of the relation dependent is a foreign key referring to empId of the relation employee. Assume that every employee has at least one associated dependent in the dependent relation. Employee (empId, empName, empAge) Dependent(depId, eId, depName, depAge) Consider the following relational algebra query: ΠempId(employee)-ΠempId (employee⋈(empId = eID)∧(empAge ≤ depAge)dependent) The above query evaluates to the set of empIds of employees whose age is greater than that of

A

some dependent.

B

all dependents

C

some of his/her dependents

D

all of his/her dependents

Which of the following statements regarding interpretation in historical writing are correct? (A) Interpretation as an essential step in historical method seems to lie beyond criticism and exposition (B) To know what a document means is as much a challenge to critical judgment as to know when or by whom was it written, or whether one may trust it (C) The literary exposition of historical data is greatly conditioned by the interpretation one places upon them (D) Factual interpretation deals with the facts of a document, not with the words Choose the most appropriate answer from the options given below:

A

(A), (C) and (D) only

B

(A), (B) and (D) only

C

(B), (C) and (D) only

D

(C) and (D) only

Statement 1: We can create foreign key constraints on relational schema derived from ER diagram Statement 2: Relational schema cannot be derived from an ER diagram

A

Both the statements are true

B

Both the statements are false

C

Statement 1 is true and Statement 2 is false

D

Statement 2 is true and statement 1 is false

A relational database system needs to maintain data about the relations, such as the schema of the relations. This is called

A

Metadata

B

Catalog

C

Log

D

Dictionary

A database of research articles in a journal uses the following schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, YEAR, PRICE) The primary key is (VOLUME, NUMBER, STARTPAGE, ENDPAGE) and the following functional dependencies exist in the schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE) → TITLE (VOLUME, NUMBER) → YEAR (VOLUME, NUMBER, STARTPAGE, ENDPAGE) → PRICE The database is redesigned to use the following schemas. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, PRICE) (VOLUME, NUMBER, YEAR) Which is the weakest normal form that the new database satisfies, but the old one does not?

A

1NF

B

2NF

C

3NF

D

BCNF

A

1 and 2

B

2 and 3

C

1 and 4

D

Only 2

Consider the following relational schema: employee(empId,empName,empDept) customer(custId,custName,salesRepId,rating) salesRepId is a foreign key referring to empId of the employee relation. Assume that each employee makes a sale to at least one customer. What does the following query return? SELECT empName FROM employee E WHERE NOT EXISTS (SELECT custId FROM customer C WHERE C.salesRepId = E.empId AND C.rating <> ’GOOD’);

A

Names of all the employees with at least one of their customers having a ‘GOOD’ rating.

B

Names of all the employees with at most one of their customers having a ‘GOOD’ rating.

C

Names of all the employees with none of their customers having a ‘GOOD’ rating.

D

Names of all the employees with all their customers having a ‘GOOD’ rating.

Consider the following relation schema Sailors(sid, sname, rating, age) Reserve(sid, bid, day) Boats(bid, bname, color) What is the equivalent of following relational algebra query in SQL query. πsname((σcolor= ‘red’Boats) ⨝ Reserves ⨝ Sailors)

A

SELECT S.sname, S.rating

FROM Sailors S, Reserves R

WHERE S.sid = R.sid AND R.bid = B.bid AND B.color = ‘red’

B

SELECT S.sname

FROM Sailors S, Reserves R, Boats B

WHERE S.bid = B.bid AND B.color = ‘red’

C

SELECT S.sname

FROM Sailors S, Reserves R, Boats B

WHERE S.sid = R.sid AND B.color = ‘red’

D

SELECT S.sname

FROM Sailors S, Reserves R, Boats B

WHERE S.sid = R.sid AND R.bid = B.bid AND B.color = ‘red’

Name	ID	COLOR
A	1	Blue
B	2	Blue
C	3	Blue
D	4	Blue
E	5	Red
F	6	Red
G	7	Red
H	8	Red
I	9	Null
J	10	Null

NAME	ID	COLOR
E	5	red
F	6	Red
G	7	Red
H	8	Red
I	9	Null
J	10	Null

NAME	ID	COLOR
A	1	Blue
B	2	Blue
C	3	Blue
D	4	Blue

NAME	ID	COLOR
E	5	Red
F	6	Red
G	7	Red
H	8	Red
I	9	Null
J	10	Null

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