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CBSE · Class 11 · Informatics Practices

Database Concepts

Standard difficulty · 20 questions · 40 marks · Time: 39 minutes

Name: Date: Score: ____ / 40

Show your working for Sections B and C. Answers are on the last page — try every question first!

Section A — Choose the correct answer8 × 1 = 8 marks
1.
A DBMS is:
  1. a kind of printer
  2. an input device
  3. a single text file
  4. software to create, store, manage and query databases
2.
What is the degree of this relation?
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1012 | 27 | Ritu | B | Patna
1101 | 28 | Pooja | A | Kochi
1461 | 29 | Manav | A | Pune
1702 | 30 | Zoya | A | Patna
1835 | 31 | Rahul | A | Kochi
1913 | 32 | Zoya | B | Kochi
  1. 4
  2. 5
  3. 6
  4. 7
3.
What is the cardinality of this relation?
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1120 | 29 | Kabir | B | Patna
1436 | 30 | Bhavna | A | Patna
1511 | 31 | Sana | B | Kochi
1519 | 32 | Pooja | B | Patna
1568 | 33 | Uday | B | Patna
1600 | 34 | Jaya | B | Agra
1822 | 35 | Sana | A | Pune
1889 | 36 | Meera | B | Pune
  1. 5
  2. 7
  3. 9
  4. 8
4.
Which attribute of this relation could be its primary key?
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1010 | 1 | Ritu | B | Patna
1034 | 2 | Manav | B | Patna
1154 | 3 | Naina | B | Kochi
1276 | 4 | Deepa | B | Pune
1612 | 5 | Uday | B | Kochi
1672 | 6 | Harsh | B | Patna
1852 | 7 | Harsh | B | Patna
1904 | 1 | Chetan | A | Patna
  1. Name
  2. RollNo
  3. AdmNo
  4. Section
5.
An attribute whose values must match the primary key of another relation is called:
  1. foreign key
  2. domain
  3. alternate key
  4. attribute
6.
The same address is copied into three different files. Which limitation of a file system is this?
  1. data dependence
  2. data isolation
  3. controlled data sharing
  4. data redundancy
7.
GUID in STUDENT is a foreign key referring to GUARDIAN. Which student's row breaks referential integrity?
Table: GUARDIAN
GUID | GName
G39 | Bhavna
G11 | Ritu
G16 | Zoya
Table: STUDENT
RollNo | SName | GUID
1 | Ishaan | G39
2 | Deepa | G45
3 | Sana | G48
4 | Asha | G11
5 | Rahul | G16
  1. Rahul
  2. Sana
  3. Ishaan
  4. Asha
8.
The candidate keys of a relation PATIENT are AdmNo, RollNo, Email, Phone. Email is chosen as its primary key. How many alternate keys does it have?
  1. 4
  2. 5
  3. 3
  4. 1
Section B — Short answer8 × 2 = 16 marks
9.
Give two limitations of a file system for storing data.
10.
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1125 | 30 | Aarav | A | Pune
1478 | 31 | Chetan | A | Pune
1510 | 32 | Lakshmi | B | Pune
1586 | 33 | Bhavna | B | Patna
1634 | 34 | Asha | B | Kochi
1825 | 35 | Kavya | B | Patna
1972 | 36 | Lakshmi | B | Pune
Find (a) its degree (b) its cardinality (c) its cardinality after 1 tuple is added and 5 deleted.
11.
Which single attributes of this relation are candidate keys? Write them separated by commas.
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1191 | 1 | Asha | A | Agra
1280 | 1 | Gauri | B | Patna
1400 | 2 | Sahil | A | Kochi
1425 | 3 | Farhan | A | Pune
1436 | 4 | Zoya | A | Kochi
1546 | 5 | Asha | A | Pune
1865 | 6 | Uday | A | Kochi
12.
The candidate keys of a relation are RollNo, BadgeNo, LibraryCardNo, MemberId. If BadgeNo is chosen as the primary key, what are the alternate keys? Write them separated by commas.
13.
GUID in STUDENT refers to GUARDIAN. Which students have a GUID that does not exist in GUARDIAN? Write their names separated by commas.
Table: GUARDIAN
GUID | GName
G44 | Zoya
G41 | Ishaan
G39 | Chetan
G18 | Gauri
Table: STUDENT
RollNo | SName | GUID
1 | Aarav | G44
2 | Bhavna | G55
3 | Pooja | G39
4 | Uday | G41
5 | Manav | G59
14.
Table: ATTENDANCE
AttDate | RollNo | Status
2026-07-07 | 35 | P
2026-07-07 | 36 | P
2026-07-07 | 37 | P
2026-07-08 | 35 | P
2026-07-08 | 36 | P
2026-07-08 | 37 | P
(a) How many tuples are there for RollNo 37? (b) What is the cardinality of the relation?
15.
A school keeps a guardian’s phone number in 4 separate files for each of its 190 students. Every student has a different guardian. How many phone numbers are stored in all, and how many would a database need if it kept them once, in a GUARDIAN table?
16.
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1015 | 30 | Zoya | A | Patna
1065 | 31 | Zoya | A | Kochi
1166 | 32 | Ishaan | B | Patna
1263 | 33 | Chetan | B | Agra
1268 | 34 | Manav | A | Agra
1323 | 35 | Farhan | B | Agra
How many different values does the attribute Section take in this relation?
Section C — Word problems4 × 4 = 16 marks
17.
Explain five limitations of a file system and how a DBMS overcomes each.
18.
Relation: STUDENT
AdmNo | RollNo | Name | Section | City
1123 | 22 | Jaya | A | Kochi
1384 | 23 | Chetan | B | Patna
1514 | 24 | Sana | B | Kochi
1703 | 25 | Sana | A | Kochi
1882 | 26 | Pooja | B | Agra
1900 | 27 | Rahul | B | Patna
(a) What are its degree and cardinality? (b) Which attributes are candidate keys? (c) If AdmNo is the primary key, which are alternate keys? (d) Why can Name not be a key?
19.
Table: GUARDIAN
GUID | GName
G29 | Jaya
G55 | Varun
G32 | Manav
Table: STUDENT
RollNo | SName | GUID
1 | Sahil | G29
2 | Aarav | G29
3 | Ritu | G32
4 | Kavya | G29
5 | Gauri | G29
6 | Tanvi | G18
(a) Which attribute is the primary key of GUARDIAN? (b) Which attribute of STUDENT is a foreign key? (c) Which students break referential integrity? (d) What should a DBMS do when such a row is inserted?
20.
Table: ATTENDANCE
AttDate | RollNo | Status
2026-07-12 | 9 | P
2026-07-12 | 34 | P
2026-07-13 | 9 | P
2026-07-13 | 34 | P
2026-07-14 | 9 | P
2026-07-14 | 34 | P
Answer Yes or No: (a) Is AttDate alone unique? (b) Is RollNo alone unique? (c) Is the pair (AttDate, RollNo) unique?
AmbifulWorksheets
Practice that never repeats
CBSE · Class 11 · Informatics Practices

Answer key

Database Concepts · AW-11IP-DBC-2026-V1 · For parents — fold back or tear off before handing the sheet to your child.

QAnswerWorking
1(d) software to create, store, manage and query databases—
2(b) 5degree = number of attributes (columns)
3(d) 8cardinality = number of tuples (rows)
4(c) AdmNoAdmNo has a different value in every row and no NULL
5(a) foreign key—
6(d) data redundancy—
7(b) SanaSana's GUID is not in GUARDIAN
8(c) 3alternate keys: AdmNo, RollNo, Phone
9Data redundancy (the same data in many files) and data inconsistency (copies that disagree); also data isolation and dependence on file formats.—
10(a) 5; (b) 7; (c) 3degree = columns; cardinality = rows; 7 + 1 − 5
11AdmNoa candidate key has a different, non-NULL value in every row
12RollNo, LibraryCardNo, MemberIdevery candidate key except the primary key
13Bhavna, Manavlook up each GUID in GUARDIAN
14(a) 2; (b) 63 students × 2 dates
15760; 1904 × 190; one per student’s guardian
162A, B
17Redundancy and inconsistency (a DBMS stores data once and links tables), data isolation (tables can be joined by keys), data dependence (programs use queries, not file layouts), uncontrolled sharing (a DBMS gives each user only the rights they need).—
18(a) degree 5, cardinality 6; (b) AdmNo, RollNo; (c) RollNo; (d) two students share a name, so Name does not identify a rowunique and non-NULL in every row
19(a) GUID; (b) GUID; (c) Tanvi; (d) reject the insertion, because the GUID must already exist in GUARDIANa foreign key value must match a primary key value in the referenced table (or be NULL)
20(a) No; (b) No; (c) Yeseach date repeats for every student and each roll number for every date; the pair appears once