Computer Science for IGCSE & O level - Databases (Section 3)

• 1

  What is data integrity?

  Odpověď

  (B)

  The accuracy and consistency of the data.
• 2

  Which data type is typically used to store whole numbers?

  Odpověď

  (B)

  INTEGER
• 3

  Which of the following are common database data types?

  Odpověď

  A

  B

  C
• 4

  Which SQL command is used to retrieve specific data from a database table?

  Odpověď

  (C)

  SELECT
• 5

  Which SQL statement is used to delete data from a database table?

  Odpověď

  (C)

  DELETE
• 6

  What are the potential problems associated with data redundancy?

  Odpověď

  A

  B

  D
• 7

  Which of the following best describes the 'normalization' process in databases?

  Odpověď

  (C)

  Organizing data to reduce redundancy and improve data integrity.
• 8

  Which statement is correct regarding the number of tables in a single-table database in this context?

  Odpověď

  (B)

  It contains only one table.
• 9

  Which of the following is true about primary keys?

  Odpověď

  B

  C
• 10

  Which of the following is an example of a data type used in databases?

  Odpověď

  (C)

  Integer
• 11

  Which command is used to create a database?

  Odpověď

  (A)

  CREATE DATABASE
• 12

  What is the purpose of the 'UNIQUE' constraint in a database?

  Odpověď

  (B)

  To prevent duplicate values in a column.
• 13

  Which SQL command is used to insert new data into a table?

  Odpověď

  (C)

  INSERT
• 14

  What is the purpose of a database backup?

  Odpověď

  (B)

  To recover data in case of loss or corruption.
• 15

  Which of the following is a benefit of using a database over a simple file system for storing data?

  Odpověď

  B

  C
• 16

  Which of the following is a key goal of database security?

  Odpověď

  B

  C
• 17

  Which of the following are typical characteristics of a good primary key?

  Odpověď

  A

  B

  C
• 18

  What is the role of the `SELECT` statement in SQL?

  Odpověď

  (C)

  To retrieve data.
• 19

  What does the term 'schema' refer to in a database context?

  Odpověď

  (B)

  The structure of the database, including tables, columns, and relationships.
• 20

  What does the 'NOT NULL' constraint ensure in a database?

  Odpověď

  (C)

  That a field must have a value.
• 21

  What does ACID properties refer to in the context of database transactions?

  Odpověď

  (B)

  Atomicity, Consistency, Isolation, Durability
• 22

  Which SQL command is used to retrieve data from a database?

  Odpověď

  (C)

  SELECT
• 23

  Which SQL clause is used to sort the results of a query?

  Odpověď

  (C)

  ORDER BY
• 24

  In the context of SQL, what does the term 'JOIN' refer to?

  Odpověď

  (B)

  A way to combine data from multiple tables based on a related column.
• 25

  Which of the following is an example of an aggregate function in SQL?

  Odpověď

  (B)

  `COUNT`
• 26

  What is the purpose of a 'constraint' in a database?

  Odpověď

  (B)

  To enforce rules and restrictions on data.
• 27

  Which of the following is NOT a characteristic of a single-table database?

  Odpověď

  (C)

  Can be used to store complex data.
• 28

  What are the advantages of using a relational database over flat files?

  Odpověď

  (D)

  All of the above.
• 29

  What is the purpose of a WHERE clause in an SQL query?

  Odpověď

  (C)

  To filter the data based on specified conditions.
• 30

  Which of the following are examples of database management software?

  Odpověď

  A

  B

  D
• 31

  Which SQL commands are used to modify the data in the database?

  Odpověď

  A

  B

  C
• 32

  What do we mean by 'data dictionary' in context of database?

  Odpověď

  (C)

  A collection of metadata about the database's structure.
• 33

  Which of the following is an example of a DML command?

  Odpověď

  B

  C
• 34

  What is the function of the `ALTER TABLE` statement in SQL?

  Odpověď

  (C)

  To modify the structure of an existing table.
• 35

  Which data type is best suited for storing currency values (e.g., money amounts) in a database?

  Odpověď

  (C)

  DECIMAL or NUMERIC
• 36

  Which of the following are essential components in database design?

  Odpověď

  A

  B

  C
• 37

  Which SQL statement is used to retrieve data from a database?

  Odpověď

  (C)

  SELECT
• 38

  What is the main function of a database?

  Odpověď

  (B)

  To store and organize data
• 39

  What is the function of an aggregate function in SQL (e.g., `SUM`, `AVG`)?

  Odpověď

  (B)

  To perform calculations on a set of values.
• 40

  What does the term 'database integrity' mean?

  Odpověď

  (B)

  The accuracy, consistency, and reliability of data.
• 41

  What does the 'ALTER TABLE' command do in SQL?

  Odpověď

  (B)

  Modifies the structure of an existing table.
• 42

  Which of the following is an example of a suitable primary key for a student table?

  Odpověď

  (C)

  Student ID
• 43

  Which SQL statement is used to modify existing data in a database table?

  Odpověď

  (C)

  UPDATE
• 44

  What is the purpose of a 'trigger' in a database?

  Odpověď

  (B)

  To automatically execute a set of actions in response to an event.
• 45

  Which of the following is a task that is typically performed during database design?

  Odpověď

  (C)

  Defining the data types for each field.
• 46

  What are some examples of the benefits of SQL?

  Odpověď

  A

  B

  C

  D
• 47

  What are the benefits of using SQL in a database?

  Odpověď

  A

  C
• 48

  What are some common validation checks that can be applied to data in a database?

  Odpověď

  A

  B

  C

  D
• 49

  Which of the following is a key characteristic of a relational database?

  Odpověď

  (B)

  Data is organized into tables with rows and columns.
• 50

  Which SQL keyword is used to group rows that have the same values in one or more columns into a summary row?

  Odpověď

  (C)

  GROUP BY