Databases

Question 1

What is a database?

Answer 1

A persistent organised store of related data on a computer system.

Question 2

In terms of databases, what is meant by the term persistent/

Answer 2

It is stored in secondary storage so that it can be accessed later.

Question 3

Why is a database organised?

Answer 3

So that data can be easily processed/queried.

Question 4

What are databases handled by?

Answer 4

Software called a DBMS.

Question 5

What does DBMS stand for?

Answer 5

Database management system.

Question 6

What must a database be able to do?

Answer 6

Create,Retrieve(Read), Update, Delete.

Question 7

What two things does the DBMS do to ensure data integrity?

Answer 7

Validation and Validation.

Question 8

What happens if data is entered incorrectly?

Answer 8

Integrity is lost.

Question 9

What is validation?

Answer 9

Check g to see if data is correct when it is first input.

Question 10

What validation could be used for an email address?

Answer 10

Checking for an @ symbol and a .co.uk/.com etc at the end.

Question 11

What is validation handled by?

Answer 11

The DBMS.

Question 12

What does the DBMS provide? (6)

Answer 12

Access to the database through different applications.
Control of the data. - security features to limit what people can do.
Backup and the ability to restore from backup in the event of a disaster.
Force referential integrity.
It controls concurrency.
Supports different query languages.

Question 13

What is referential integrity?

Answer 13

A concept of relational databases which states that the table relationships must always be consistent.

Question 14

What is concurrency?

Answer 14

Locking the database so only one user can edit the data.

Question 15

What is a table also known as?

Answer 15

An entity.

Question 16

What is a record?

Answer 16

A row in a database.

Question 17

What is a field?

Answer 17

A column in a database.

Question 18

What is a primary key?

Answer 18

The attribute that is unique to each record.

Question 19

What is a foreign key?

Answer 19

The primary key that links two entities.

Question 20

What are the two types of databases?

Answer 20

Flat file and Relational

Question 21

What type of database signs primary and foreign keys?

Answer 21

Relational databases.

Question 22

What is data redundancy?

Answer 22

Data that is needlessly repeated.

Question 23

What can data redundancy lead to?

Answer 23

Complex programming problems.

Question 24

What is a module?

Answer 24

A specific piece of software used to carry out a task.

Question 25

What is a form?

Answer 25

A user friendly way to enter data into a database, it can involved buttons, tick boxes and menus.

Question 26

What is a report?

Answer 26

A way of presenting data up its information cannot not be changed.

Question 27

What is a graph?

Answer 27

A visual representation of data that can be used for comparisons.

Question 28

What are the features of relational databases?

Answer 28

Stores data in tables.
Each data is about an entity.
The columns are called attributes, a single column is called a field.
Each recorded must have a primary key to make it uniquely identifiable.

Question 29

Explain what a relational database is. [3 Marks]

Answer 29

A relational database is a database that consist of multiple tables that are linked together by primary and foreign keys so that data can be extracted easily and there is no data redundancy.

Question 30

What is a query used for?

Answer 30

Extracting a subset of data from a database using conditions.

Question 31

What are the two operators used in querying?

Answer 31

AND

OR