Computer Science for IGCSE & O level - Databases (Section 3)
1
Trả lời(B)
The accuracy and consistency of the data.
2
Which data type is typically used to store whole numbers?
3
Which of the following are common database data types?
4
Which SQL command is used to retrieve specific data from a database table?
5
Which SQL statement is used to delete data from a database table?
6
What are the potential problems associated with data redundancy?
7
Which of the following best describes the 'normalization' process in databases?
Trả lời(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?
Trả lời(B)
It contains only one table.
9
Which of the following is true about primary keys?
10
Which of the following is an example of a data type used in databases?
11
Which command is used to create a database?
12
What is the purpose of the 'UNIQUE' constraint in a database?
Trả lời(B)
To prevent duplicate values in a column.
13
Which SQL command is used to insert new data into a table?
14
What is the purpose of a database backup?
Trả lời(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?
16
Which of the following is a key goal of database security?
17
Which of the following are typical characteristics of a good primary key?
18
What is the role of the `SELECT` statement in SQL?
19
What does the term 'schema' refer to in a database context?
Trả lời(B)
The structure of the database, including tables, columns, and relationships.
20
What does the 'NOT NULL' constraint ensure in a database?
Trả lời(C)
That a field must have a value.
21
What does ACID properties refer to in the context of database transactions?
Trả lời(B)
Atomicity, Consistency, Isolation, Durability
22
Which SQL command is used to retrieve data from a database?
23
Which SQL clause is used to sort the results of a query?
24
In the context of SQL, what does the term 'JOIN' refer to?
Trả lời(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?
26
What is the purpose of a 'constraint' in a database?
Trả lời(B)
To enforce rules and restrictions on data.
27
Which of the following is NOT a characteristic of a single-table database?
Trả lời(C)
Can be used to store complex data.
28
What are the advantages of using a relational database over flat files?
29
What is the purpose of a WHERE clause in an SQL query?
Trả lời(C)
To filter the data based on specified conditions.
30
Which of the following are examples of database management software?
31
Which SQL commands are used to modify the data in the database?
32
What do we mean by 'data dictionary' in context of database?
Trả lời(C)
A collection of metadata about the database's structure.
33
Which of the following is an example of a DML command?
34
What is the function of the `ALTER TABLE` statement in SQL?
Trả lời(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?
36
Which of the following are essential components in database design?
37
Which SQL statement is used to retrieve data from a database?
38
What is the main function of a database?
Trả lời(B)
To store and organize data
39
What is the function of an aggregate function in SQL (e.g., `SUM`, `AVG`)?
Trả lời(B)
To perform calculations on a set of values.
40
What does the term 'database integrity' mean?
Trả lời(B)
The accuracy, consistency, and reliability of data.
41
What does the 'ALTER TABLE' command do in SQL?
Trả lời(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?
43
Which SQL statement is used to modify existing data in a database table?
44
What is the purpose of a 'trigger' in a database?
Trả lời(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?
Trả lời(C)
Defining the data types for each field.
46
What are some examples of the benefits of SQL?
47
What are the benefits of using SQL in a database?
48
What are some common validation checks that can be applied to data in a database?
49
Which of the following is a key characteristic of a relational database?
Trả lời(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?
