Sign In

Computer Science for IGCSE & O level - Databases (Section 6)

1
Which clause is used to sort the records in an SQL query?
Answer
(C)
ORDER BY
2
What is the purpose of a validation rule for a field?
Answer
(B)
To ensure data accuracy and consistency
3
Which SQL command is used to remove a table from a database?
Answer
(B)
DROP TABLE
4
Which of the following is an example of a data type?
Answer
(C)
Integer
5
What is the benefit of using a database system over a simple file system for storing data?
Answer
(B)
Databases offer better data organization, data integrity, and allow for more efficient data retrieval.
6
What does the term 'data warehousing' refer to?
Answer
(C)
A system for storing and analyzing large volumes of historical data.
7
What is the purpose of the `GROUP BY` clause in SQL?
Answer
(C)
To combine rows with the same values in a specified column into a summary row.
8
Which SQL command is used to change existing data in a table?
Answer
(C)
UPDATE
9
What is the purpose of the `GROUP BY` clause in an SQL query?
Answer
(C)
To combine rows that have the same values in one or more columns into a summary row.
10
What are the benefits of using a database?
Answer
A
B
D
11
In a database, what does the term 'field' represent?
Answer
(B)
A single item of data within a record.
12
What is the purpose of a SQL script?
Answer
(B)
To perform a task on a database.
13
What is the main function of a database management system (DBMS)?
Answer
(C)
To manage and organize data.
14
What is the main function of a 'query' in a database?
Answer
(B)
To retrieve or manipulate data.
15
What is the purpose of the 'WHERE' clause in an SQL query?
Answer
(C)
To filter the results based on specified criteria.
16
What is a transaction in the context of databases?
Answer
(B)
A logical unit of work that is treated as a single operation.
17
What is a database index used for?
Answer
(A)
To speed up data retrieval.
18
What is the purpose of the `ROLLBACK` statement in a database transaction?
Answer
(B)
To discard the changes made during a transaction and restore the database to its previous state.
19
What is a primary key used for in a database table?
Answer
(B)
To ensure the unique identification of each record in the table.
20
What is a transaction in a database context?
Answer
(B)
A sequence of operations performed as a single unit of work.
21
What is the primary function of the `GROUP BY` clause in SQL?
Answer
(C)
To aggregate data based on one or more columns.
22
What is a field in a database table?
Answer
(B)
The individual piece of information stored in a database.
23
Which of the following is an example of a database relationship?
Answer
(D)
All of the above
24
What is the purpose of the `FROM` clause in an SQL statement?
Answer
(B)
To identify the table(s) from which to retrieve data.
25
What is data redundancy in a database?
Answer
(B)
The duplication of data within the database.
26
Which of the following are part of the ACID properties?
Answer
A
B
D
27
Which keyword is used to add a primary key to a table?
Answer
(B)
ALTER TABLE ... ADD PRIMARY KEY
28
In the context of a database table, what is a 'field' also known as?
Answer
(C)
An attribute or column.
29
Which of the following data types would be most appropriate for storing a person's date of birth?
Answer
(C)
DATE/TIME
30
Which of the following is a type of database relationship?
Answer
(D)
All of the above
31
Which components must be set up in database?
Answer
A
B
C
D
32
What is the role of a 'data type' in a database?
Answer
(B)
To determine how data is stored and displayed.
33
What is the purpose of using a database management system (DBMS)?
Answer
A
B
C
34
Which of the following is a key component of database design?
Answer
A
B
C
D
35
In an SQL query, what does the `NULL` value represent?
Answer
(C)
A missing or unknown value.
36
Which of the following is an example of a DDL command?
Answer
B
C
37
What does ACID properties stand for in database transaction?
Answer
(A)
Atomicity, Consistency, Isolation, Durability
38
In SQL, what does the `UPDATE` statement allow you to do?
Answer
(C)
Modify existing data.
39
What does a database table store?
Answer
(B)
Data organized in rows and columns.
40
Which command is used to insert new data into a database table?
Answer
(C)
INSERT
41
What type of data should be stored in a column with the data type `VARCHAR`?
Answer
(C)
Text strings of varying lengths.
42
What is a foreign key used for?
Answer
B
C
43
What are the purposes of using indexes in a database?
Answer
(A)
To speed up data retrieval
44
Which of the following is a key advantage of using a relational database?
Answer
(C)
Ease of data retrieval and manipulation.
45
Which factors should be considered when choosing a data type for a database field?
Answer
A
B
C
D
46
What does the acronym DDL stand for in the context of databases?
Answer
(A)
Data Definition Language
47
What is the purpose of `JOIN` command in SQL?
Answer
(C)
To combine rows from two or more tables based on a related column.
48
What is the main goal of the validation rules?
Answer
(B)
To ensure data integrity
49
Which of the following is often used to identify multiple records in a relational database?
Answer
(A)
Unique values
50
What is the purpose of a 'constraint' in a database?
Answer
(B)
To enforce rules and restrictions on data.