Computer Science for IGCSE & O level - Databases (Section 1)
1
What does the 'Length check' validation rule check for?
Απάντηση(C)
The number of characters in the data.
2
What is the purpose of the `Format` property for a field in a database?
Απάντηση(B)
To control how data is displayed.
3
Which of the following is true about the `FROM` clause in an SQL query?
Απάντηση(A)
It specifies which table to query.
4
Which of the following is an example of a DDL (Data Definition Language) command?
5
Which of the following is NOT a typical function of a database management system (DBMS)?
Απάντηση(D)
Operating system management
6
What is the purpose of the 'Required' property for a field in a database?
Απάντηση(C)
To prevent the field from being left blank.
7
What is the purpose of the 'WHERE' clause in an SQL query?
Απάντηση(C)
To filter the records based on a condition.
8
What does the term 'database' primarily refer to?
Απάντηση(C)
An organized collection of data.
9
Which SQL command is used to delete records from a table?
10
What does the 'SUM' function do in an SQL query?
Απάντηση(C)
Calculates the sum of values in a column.
11
What is the purpose of a primary key in a database table?
Απάντηση(B)
To identify a record uniquely.
12
What is a database used for in healthcare?
13
In the context of the provided material, what is the purpose of validation checks?
Απάντηση(B)
To ensure data is accurate and meets specific requirements.
14
What is an example of DML in SQL?
15
What does the abbreviation 'DBMS' stand for?
Απάντηση(D)
Database Management System
16
What does the SQL command 'CREATE TABLE' do?
Απάντηση(B)
Creates a table definition.
17
What type of data is typically stored in an `INTEGER` data type?
18
What are some common types of validation checks?
19
Which data type would you most likely use to store a value that could be TRUE or FALSE?
20
Which data type would be most appropriate for storing a person's first name?
21
What is the primary purpose of a database?
Απάντηση(A)
To store and organize data
22
What is the function of the `ALTER TABLE` SQL command?
Απάντηση(B)
To modify an existing table structure.
23
What is the correct SQL command to retrieve all fields from a table named 'Patients'?
24
What is an example of a suitable validation rule for a date of birth field?
25
What is a single-table database?
Απάντηση(B)
A database containing only one table.
26
How are SQL statements written?
27
In the context of a database, what does 'normalization' refer to?
Απάντηση(B)
Organizing data to reduce redundancy and improve data integrity.
28
In a car database, how could you use SQL to find all combinations of red seat colour and silver paint colour?
Απάντηση(A)
SELECT * FROM CAR WHERE SeatColour = 'Red' AND PaintColour = 'Silver';
29
Which of the following are benefits of using databases?
30
What is the purpose of the `COUNT` function in SQL?
Απάντηση(B)
To count the number of records that meet certain criteria.
31
What does the term 'record' refer to in a database?
Απάντηση(C)
A single instance of data stored in a table.
32
What would the SQL command be to display the family name, other names and email address in alphabetical order of the family name?
Απάντηση(A)
SELECT FamilyName, OtherNames, EmailAddress FROM Students ORDER BY FamilyName;
33
What is the purpose of an `SQL script`?
Απάντηση(C)
To perform a specific task, often to be reused.
34
What data type is most appropriate for storing a patient's ward number?
35
What is one of the functionalities in the 'Extension Activity'?
Απάντηση(B)
Use DML commands to set up the PATENT database.
36
If a database table stores information about books, what could be a suitable primary key?
37
Which of the following is NOT an example of a validation check?
38
Which of the following statements is true regarding the `SELECT` statement in SQL?
Απάντηση(B)
It's used to retrieve data from one or more tables.
39
What is the purpose of a primary key in a database?
Απάντηση(B)
To uniquely identify each record in a table.
40
What is the difference between the terms 'table' and 'database'?
Απάντηση(B)
A database is a container for tables.
41
In a database, what does 'normalization' refer to?
Απάντηση(B)
The process of organizing data to reduce redundancy and improve data integrity.
42
What is a data type used for in a database?
Απάντηση(D)
To classify how data is stored and displayed.
43
What does DDL stand for in the context of databases?
44
In the provided example, what would be the correct SQL command to find records where SeatColour is 'Red' AND (White OR Silver)?
45
What are SQL scripts generally used for?
Απάντηση(B)
Automating database tasks.
46
What components make up a relational database?
47
In an SQL query, what does the `*` symbol represent?
48
Which of the following are considered key benefits of using a database?
49
What is the primary purpose of data redundancy?
Απάντηση(D)
To create multiple copies of data for backup and disaster recovery.
50
What does the term 'field' refer to in a database?
