IGCSE · Computer Science 0478 · Databases & logic

Databases & SQL: IGCSE Computer Science questions with answers

Free Databases & SQL questions for IGCSE Computer Science (0478), part of Databases & logic. Each question has the answer and the marking points an examiner would look for.

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Databases & SQL practice questions

Question 1Structured · 7 marks

A shop stores data in a database table called PRODUCTS.

ProductID	Name	Category	Price	Stock
P101	Puzzle	Toy	15.18	34
P102	Atlas	Book	5.78	51
P103	Chess	Game	8.53	24
P104	Robot	Toy	15.62	39
P105	Novel	Book	22.62	55
P106	Cards	Game	19.77	55
P107	Kite	Toy	4.31	49

Table 1.1

(a)

State the field that is the most suitable primary key.

[1]

(b)

Write an SQL query to display the Name and Price of products in the category Toy with a price greater than 12, in descending order of Price.

[4]

(c)

State the output of: SELECT Name FROM PRODUCTS WHERE Stock < 18;

[2]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	ProductID ProductID B1	1
(b)	SELECT Name, Price FROM PRODUCTS WHERE Category = 'Toy' AND Price > 12 ORDER BY Price DESC; SELECT Name, Price B1 FROM PRODUCTS B1 WHERE Category = 'Toy' AND Price > 12 B1 ORDER BY Price DESC B1	4
(c)	no records All correct names B2 B1 for one error/omission	2

Question 2Structured · 6 marks

A school stores data in several database tables. The table shows some of the fields.

(a)

Identify the most suitable data type for each field.

Field	Data type
the height of a plant in metres
a parent’s email address
the price of a meal
whether a member has paid

Table 2.1

[4]

(b)

Explain why a phone number is not stored as an integer.

[2]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	the height of a plant in metres: real; a parent’s email address: text / string; the price of a meal: real; whether a member has paid: Boolean the height of a plant in metres: real B1 a parent’s email address: text / string B1 the price of a meal: real B1 whether a member has paid: Boolean B1	4
(b)	It may start with 0 / contain spaces or + signs, which would be lost; no calculations are done on it Leading zeros / spaces / symbols would be lost B1 It is never used in calculations B1	2

Question 3Structured · 6 marks

A sports centre stores data about its trainers in a table called TRAINERS.

TrainerID	Name	Site	Hours	YearJoined
T201	Asha	East	12	2022
T202	Ben	North	8	2024
T203	Chen	North	5	2022
T204	Dina	North	3	2024
T205	Eli	South	4	2020
T206	Farah	North	9	2016
T207	Gita	South	6	2020

Table 3.1

(a)

State the number of records and the number of fields in the table.

[2]

(b)

State the output of: SELECT COUNT(*) FROM TRAINERS WHERE Site = 'East';

[1]

(c)

Write an SQL query to output the total Hours worked by trainers who joined after 2020.

[3]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	7 records, 5 fields 7 records B1 5 fields B1	2
(b)	1 1 B1	1
(c)	SELECT SUM(Hours) FROM TRAINERS WHERE YearJoined > 2020; (gives 28) SELECT SUM(Hours) B1 FROM TRAINERS B1 WHERE YearJoined > 2020 (accept >= 2021) B1	3

Question 4Structured · 2 marks

(a)

State what is meant by the term primary key.

[1]

(b)

State what is meant by the term record.

[1]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	A field that uniquely identifies each record A field that uniquely identifies each record B1	1
(b)	A collection of related fields about one item A collection of related fields about one item B1	1

Question 5Structured · 7 marks

A shop stores data in a database table called PRODUCTS.

ProductID	Name	Category	Price	Stock
P101	Puzzle	Toy	8.05	9
P102	Atlas	Book	10.07	51
P103	Chess	Game	30.95	40
P104	Robot	Toy	18.21	34
P105	Novel	Book	23.16	57
P106	Cards	Game	29.35	17
P107	Kite	Toy	9.55	34

Table 5.1

(a)

State the field that is the most suitable primary key.

[1]

(b)

Write an SQL query to display the Name and Price of products in the category Game with a price greater than 27, in descending order of Price.

[4]

(c)

State the output of: SELECT Name FROM PRODUCTS WHERE Stock < 20;

[2]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	ProductID ProductID B1	1
(b)	SELECT Name, Price FROM PRODUCTS WHERE Category = 'Game' AND Price > 27 ORDER BY Price DESC; SELECT Name, Price B1 FROM PRODUCTS B1 WHERE Category = 'Game' AND Price > 27 B1 ORDER BY Price DESC B1	4
(c)	Puzzle, Cards All correct names B2 B1 for one error/omission	2

Question 6Structured · 6 marks

A sports centre stores data about its trainers in a table called TRAINERS.

TrainerID	Name	Site	Hours	YearJoined
T201	Asha	North	3	2017
T202	Ben	East	11	2023
T203	Chen	East	6	2021
T204	Dina	South	6	2023
T205	Eli	South	7	2019
T206	Farah	East	9	2019
T207	Gita	South	5	2017

Table 6.1

(a)

State the number of records and the number of fields in the table.

[2]

(b)

State the output of: SELECT COUNT(*) FROM TRAINERS WHERE Site = 'South';

[1]

(c)

Write an SQL query to output the total Hours worked by trainers who joined after 2020.

[3]

Show answers and mark scheme

Part	Answer and marking points	Marks
(a)	7 records, 5 fields 7 records B1 5 fields B1	2
(b)	3 3 B1	1
(c)	SELECT SUM(Hours) FROM TRAINERS WHERE YearJoined > 2020; (gives 23) SELECT SUM(Hours) B1 FROM TRAINERS B1 WHERE YearJoined > 2020 (accept >= 2021) B1	3

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Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in