lOMoAR cPSD| 47715245
,UNIVERSITY EXAMINATIONS
MAY/JUN 2025
INF2603
Database 1
100 Marks
Duration 2 Hours
EXAMINERS:
FIRST: Mr ME Bogopa
SECOND: Ms CL Hlengwa
This paper consists of 5 pages.
Instructions:
1. Answer all questions.
2. The marks for each question are given in brackets next to the question.
3. Please answer the questions in the order in which they have been set.
4. You signed an Honesty Declaration. This means you will complete this
paper on your own and without help.
5. This final pdf document should not be password protected.
6. Convert all the pages into a single PDF file.
7. Poorly scanned and hard to read answer files will result in a zero mark.
8. Once your document meets all the criteria, then you can upload the file
to myAdmin.
, GOOD LUCK.
QUESTION 1 [20 marks]
Carefully select the most correct answer to each of the following questions. Please write
down only the question number and corresponding to it put the correct option’s number
(e.g. Qu. 11. (e)) (2 marks each):
1. The _____ is actually a system-created database whose tables store the user/designer-
created database characteristics and contents.
a. unique index
b. database tuple
c. system catalogue
d. systematic database
2. Within the relational model, tables are known as ____, columns of tables are referred to
as ____ and rows of tables are called ____.
a. tuples, attributes, entities
b. relations, attributes, tuples
c. relations, tuples, attributes
d. relation, attributes, tuples
3. Which of the following returns all tuples in one relation that are not found in the other
relation?
a. PRODUCT
b. SELECT
c. PROJECT
d. DIFFERENCE
4. The STUDENT table’s primary key is STUDENT_NUMB. The STUDENT primary key
column has no null entries, and all entries are unique. This is an example of _____
integrity. a. null
b. entity
c. relational
d. referential
5. Which of the following is true of NoSQL databases?
a. They do not support distributed database architectures.
b. They are not based on the relational model.
c. They are geared toward transaction consistency rather than performance.
d. They do not support very large amounts of sparse data.
,6. Which of the following is NOT a true statement about constraints:
a. Constraints are important because they help to ensure data integrity.
b. Constraints support high-level inserts, updates and deletes.
c. Constraints are normally expressed in the form of rules.
d. A constraint is a restriction placed on the data.
7. What is the purpose of an entity cluster?
a. define physical database storage for related entities
b. group related entities into a single table
c. improve readability of the ERD
d. make the ERD more complex
8The Chen notation identifies a weak entity by using a double-walled entity rectangle.
a. True
b. False
9. Which of the following special operator checks whether an attribute value
matches any value within a value list?
a. IN
b. LIKE
c. EXISTS
d. BETWEEN
10. If the attribute (A) is functionally dependent on a composite key (B) but not on
any subset of that composite key, the attribute (A) is fully functionally dependent on
(B). a. True
b. False
1. (c)
2. (b)
3. (d)
4. (b)
5. (b)
6. (b)
7. (b)
8. (a)
9. (a)
10. (a)
, Below are detailed explanations for each answer.
1. (c) System catalogue — The system catalogue (also called the data
dictionary or system catalog) is a system-created set of tables that
store metadata about the database: definitions of tables, columns,
constraints, indexes, users, privileges, etc. It is distinct from user-
created tables (which store user data). The other options are
incorrect: a unique index is a structure to enforce uniqueness; a
database tuple is a row in a table; “systematic database” is not a
standard term.
2. (b) relations, attributes, tuples — In the relational model a table is
formally called a relation, a column is an attribute, and a row is a
tuple. (Option (d) is close but uses the singular “relation” in the first
slot and option (b) is the conventional phrasing used in definitions
and textbooks.)
3. (d) DIFFERENCE — The relational algebra difference operator (R
− S) returns all tuples that are in relation R and not in relation S.
PRODUCT returns Cartesian product, SELECT filters tuples,
PROJECT selects columns.
4. (b) Entity integrity — The rule that a primary-key column must
contain unique, non-NULL values is the entity-integrity rule.
Referential integrity concerns foreign keys referencing primary
keys in other tables. “Null integrity” and “relational integrity” are
not standard labels for this precise rule.
5. (b) They are not based on the relational model. — NoSQL
databases (key-value stores, document stores, wide-column stores,
graph DBs) are intentionally not based on the relational model; they
typically allow flexible schemas, horizontal scaling, and different
consistency/performance trade-offs. The other statements are false:
NoSQL often supports distributed architectures, it generally favors
performance and scalability (sometimes at the cost of strict
ACID/transaction consistency), and it does support very large and
often sparse data sets.
6. (b) Constraints support high-level inserts, updates and deletes.
(NOT true) — Constraints are restrictions placed on the data
(foreign keys, check constraints, uniqueness, not-null) to ensure
integrity. They do not “support” operations in the sense of enabling
,UNIVERSITY EXAMINATIONS
MAY/JUN 2025
INF2603
Database 1
100 Marks
Duration 2 Hours
EXAMINERS:
FIRST: Mr ME Bogopa
SECOND: Ms CL Hlengwa
This paper consists of 5 pages.
Instructions:
1. Answer all questions.
2. The marks for each question are given in brackets next to the question.
3. Please answer the questions in the order in which they have been set.
4. You signed an Honesty Declaration. This means you will complete this
paper on your own and without help.
5. This final pdf document should not be password protected.
6. Convert all the pages into a single PDF file.
7. Poorly scanned and hard to read answer files will result in a zero mark.
8. Once your document meets all the criteria, then you can upload the file
to myAdmin.
, GOOD LUCK.
QUESTION 1 [20 marks]
Carefully select the most correct answer to each of the following questions. Please write
down only the question number and corresponding to it put the correct option’s number
(e.g. Qu. 11. (e)) (2 marks each):
1. The _____ is actually a system-created database whose tables store the user/designer-
created database characteristics and contents.
a. unique index
b. database tuple
c. system catalogue
d. systematic database
2. Within the relational model, tables are known as ____, columns of tables are referred to
as ____ and rows of tables are called ____.
a. tuples, attributes, entities
b. relations, attributes, tuples
c. relations, tuples, attributes
d. relation, attributes, tuples
3. Which of the following returns all tuples in one relation that are not found in the other
relation?
a. PRODUCT
b. SELECT
c. PROJECT
d. DIFFERENCE
4. The STUDENT table’s primary key is STUDENT_NUMB. The STUDENT primary key
column has no null entries, and all entries are unique. This is an example of _____
integrity. a. null
b. entity
c. relational
d. referential
5. Which of the following is true of NoSQL databases?
a. They do not support distributed database architectures.
b. They are not based on the relational model.
c. They are geared toward transaction consistency rather than performance.
d. They do not support very large amounts of sparse data.
,6. Which of the following is NOT a true statement about constraints:
a. Constraints are important because they help to ensure data integrity.
b. Constraints support high-level inserts, updates and deletes.
c. Constraints are normally expressed in the form of rules.
d. A constraint is a restriction placed on the data.
7. What is the purpose of an entity cluster?
a. define physical database storage for related entities
b. group related entities into a single table
c. improve readability of the ERD
d. make the ERD more complex
8The Chen notation identifies a weak entity by using a double-walled entity rectangle.
a. True
b. False
9. Which of the following special operator checks whether an attribute value
matches any value within a value list?
a. IN
b. LIKE
c. EXISTS
d. BETWEEN
10. If the attribute (A) is functionally dependent on a composite key (B) but not on
any subset of that composite key, the attribute (A) is fully functionally dependent on
(B). a. True
b. False
1. (c)
2. (b)
3. (d)
4. (b)
5. (b)
6. (b)
7. (b)
8. (a)
9. (a)
10. (a)
, Below are detailed explanations for each answer.
1. (c) System catalogue — The system catalogue (also called the data
dictionary or system catalog) is a system-created set of tables that
store metadata about the database: definitions of tables, columns,
constraints, indexes, users, privileges, etc. It is distinct from user-
created tables (which store user data). The other options are
incorrect: a unique index is a structure to enforce uniqueness; a
database tuple is a row in a table; “systematic database” is not a
standard term.
2. (b) relations, attributes, tuples — In the relational model a table is
formally called a relation, a column is an attribute, and a row is a
tuple. (Option (d) is close but uses the singular “relation” in the first
slot and option (b) is the conventional phrasing used in definitions
and textbooks.)
3. (d) DIFFERENCE — The relational algebra difference operator (R
− S) returns all tuples that are in relation R and not in relation S.
PRODUCT returns Cartesian product, SELECT filters tuples,
PROJECT selects columns.
4. (b) Entity integrity — The rule that a primary-key column must
contain unique, non-NULL values is the entity-integrity rule.
Referential integrity concerns foreign keys referencing primary
keys in other tables. “Null integrity” and “relational integrity” are
not standard labels for this precise rule.
5. (b) They are not based on the relational model. — NoSQL
databases (key-value stores, document stores, wide-column stores,
graph DBs) are intentionally not based on the relational model; they
typically allow flexible schemas, horizontal scaling, and different
consistency/performance trade-offs. The other statements are false:
NoSQL often supports distributed architectures, it generally favors
performance and scalability (sometimes at the cost of strict
ACID/transaction consistency), and it does support very large and
often sparse data sets.
6. (b) Constraints support high-level inserts, updates and deletes.
(NOT true) — Constraints are restrictions placed on the data
(foreign keys, check constraints, uniqueness, not-null) to ensure
integrity. They do not “support” operations in the sense of enabling
